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prof. Mgr. Petr Páta, Ph.D.

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Assessing the Spectral Characteristics of Dye- and Pigment-Based Inkjet Prints by VNIR Hyperspectral Imaging

  • DOI: 10.3390/s22020603
  • Link: https://doi.org/10.3390/s22020603
  • Department: Department of Radioelectronics
  • Annotation:
    Fine art photography, paper documents, and other parts of printing that aim to keep value are searching for credible techniques and mediums suitable for long-term archiving purposes. In general, long-lasting pigment-based inks are used for archival print creation. However, they are very often replaced or forged by dye-based inks, with lower fade resistance and, therefore, lower archiving potential. Frequently, the difference between the dye- and pigment-based prints is hard to uncover. Finding a simple tool for countrified identification is, therefore, necessary. This paper assesses the spectral characteristics of dye- and pigment-based ink prints using visible near-infrared (VNIR) hyperspectral imaging. The main aim is to show the spectral differences between these ink prints using a hyperspectral camera and subsequent hyperspectral image processing. Two diverse printers were exploited for comparison, a hobby dye-based EPSON L1800 and a professional pigment-based EPSON SC-P9500. The identical prints created via these printers on three different types of photo paper were recaptured by the hyperspectral camera. The acquired pixel values were studied in terms of spectral characteristics and principal component analysis (PCA). In addition, the obtained spectral differences were quantified by the selected spectral metrics. The possible usage for print forgery detection via VNIR hyperspectral imaging is discussed in the results.

Broadband Wollaston prism with a large output beam separation based on mercurous halides

  • DOI: 10.1364/OE.477544
  • Link: https://doi.org/10.1364/OE.477544
  • Department: Department of Radioelectronics
  • Annotation:
    The paper proposes a Wollaston-type crystal polarizer suitable for broadband operation within the visible spectral band up to the far infrared band based on unique optical materials, mercurous halides (Hg2X2). This paper introduces the general characteristics and optical properties of these birefringent tetragonal optical materials, as well as the general description of a Wollaston prism and the process of its parameter optimization. In general, the Wollaston polarizer is constructed from two combined wedge-shaped prisms. The key parameters that affect the properties of the Wollaston polarizer are then the cut angle of these two prisms and the refractive index of the exploited optical cement (immersion) that bonds the prisms together. The optimal prism cut angles and immersion refractive index are investigated to maximize the Wollaston parameters, such as the transmittance of the polarized radiation and the separation angle of the output orthogonally polarized beams. This process is significantly dependent on the characteristics of all selected mercurous halides (Hg2Cl2, Hg2Br2, Hg2I2). The optimal values of the prism cut angle for each material are selected based on the outlined results. In addition, the Wollaston prism behaviour regarding real radiation propagation is modelled in detail via the Zemax optical studio. The presented models aim to aid in the real design and fabrication of a broadband Wollaston polarizer based on mercurous halides.

Quasi-collinear IR AOTF based on mercurous halide single crystals for spatio-spectral hyperspectral imaging

  • DOI: 10.1364/OE.420571
  • Link: https://doi.org/10.1364/OE.420571
  • Department: Department of Radioelectronics
  • Annotation:
    The paper aims to show the advantages of the infrared-optimised quasi-collinear AOTF (acousto-optic tunable filter) for the spatio-spectral hyperspectral imaging system. The optimisation process is presented based on the selected tetragonal anisotropic materials with exceptional optical and acousto-optical properties in IR (infrared) spectral region. These materials are further compared in terms of their features and suitability for AOTF design. The spectral resolution is considered as the main optimising parameter. Resulting from the analysis, the mercurous chloride (Hg2Cl2) single crystal is selected as a representative of the mercurous halide family for the presentation of the quasi-collinear AOTF model operating in LWIR (long-wave infrared) spectral band. The overall parameters of the AOTF model such as spectral resolution, chromatic field of view, acoustic frequency, and operational power requirements are estimated and discussed in results.

Activity profile, mass distribution index, radiants, and orbits of the 2018 Draconid meteor shower outburst

  • DOI: 10.1016/j.pss.2020.104871
  • Link: https://doi.org/10.1016/j.pss.2020.104871
  • Department: Department of Radioelectronics
  • Annotation:
    An outburst of Draconid meteor shower was predicted for October 8 to 9, 2018. Using a variety of video and photographic cameras covering a broad range of magnitudes, the shower activity profile was measured. The main peak was observed at the solar longitude , what is equivalent to UT. This result is in good agreement with other reports as well as with the predictions. Two other sub-peaks or enhancements of the activity were detected later in the night. The analysis of the mass distribution index evolution and the comparison with other experiments suggests that the later activity was probably caused by the mixture of the different trails of the stream which were more dispersed. The flux of the meteoroids was three to four times smaller in comparison with the 2011 Draconid outburst. When comparing the radiants and velocities of the observed meteors with the model data, good agreement was found for the right ascension and velocity but a small offset of about +0.5∘ was observed in declination. On the other hand, the mean main peak radiant fits well the model of Maslov (2011).

Assessing Cloud Segmentation in the Chromacity Diagram of All-Sky Images

  • DOI: 10.3390/rs12111902
  • Link: https://doi.org/10.3390/rs12111902
  • Department: Department of Radioelectronics
  • Annotation:
    All-sky imaging systems are currently very popular. They are used in ground-based meteorological stations and as a crucial part of the weather monitors for autonomous robotic telescopes. Data from all-sky imaging cameras provide important information for controlling meteorological stations and telescopes, and they have specific characteristics different from widely-used imaging systems. A particularly promising and useful application of all-sky cameras is for remote sensing of cloud cover. Post-processing of the image data obtained from all-sky imaging cameras for automatic cloud detection and for cloud classification is a very demanding task. Accurate and rapid cloud detection can provide a good way to forecast weather events such as torrential rainfalls. However, the algorithms that are used must be specifically calibrated on data from the all-sky camera in order to set up an automatic cloud detection system. This paper presents an assessment of a modified k-means++ color-based segmentation algorithm specifically adjusted to the WILLIAM (WIde-field aLL-sky Image Analyzing Monitoring system) ground-based remote all-sky imaging system for cloud detection. The segmentation method is assessed in two different color-spaces (L*a*b and XYZ). Moreover, the proposed algorithm is tested on our public WMD database (WILLIAM Meteo Database) of annotated all-sky image data, which was created specifically for testing purposes. The WMD database is available for public use. In this paper, we present a comparison of selected color-spaces and assess their suitability for the cloud color segmentation based on all-sky images. In addition, we investigate the distribution of the segmented cloud phenomena present on the all-sky images based on the color-spaces channels. In the last part of this work, we propose and discuss the possible exploitation of the color-based k-means++ segmentation method as a preprocessing step towards cloud classification in all-sky images.

Analysis and performance of non-circular polygonal polynomials in the wavefront modeling

  • Authors: Janout, P., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Proceedings Volume 10743, Optical Modeling and Performance Predictions X. Bellingham: SPIE, 2018. SPIE PROCEEDINGS. vol. 10743. ISSN 1996-756X. ISBN 9781510620582.
  • Year: 2018
  • DOI: 10.1117/12.2321302
  • Link: https://doi.org/10.1117/12.2321302
  • Department: Department of Radioelectronics
  • Annotation:
    Imaging system design is not limited to circular aperture shapes. However, non-circular apertures require a different set of polynomials, because broadly used Zernike polynomials are not orthogonal over non-circular shapes. Applying the Gram-Schmidt orthogonalization process provide the adopted set of orthogonal polynomials over selected non-circular aperture shape. However, when the aperture shape is complicated, non-symmetrical, the resulting set of polynomials can be very complex. In the case of odd-sided polygons is the analytical form of the polynomials inappropriate due to their complexity and these polynomials have to be expressed in their numerical form. Concerning the laborious complexity of some non-circular polynomials, we analyze the desired accuracy of such polynomials and their performance of the wavefront modeling according to classical circular Zernike polynomials.

Experimental setup for the quality evaluation of optical materials

  • DOI: 10.1109/RADIOELEK.2018.8376400
  • Link: https://doi.org/10.1109/RADIOELEK.2018.8376400
  • Department: Department of Radioelectronics
  • Annotation:
    Modern photonic elements and systems are based upon novel optical materials. The material optical quality is a crucial parameter for any photonic application. The paper deals with the design and initial verification of optical quality evaluation system allowing fast near-mass-production evaluation of several qualitative parameters both spatially distributed and integral. The semi-automatic setup includes the schlieren-optics imaging, OFT (optical Fourier transform) imaging and integral metrics for overall quantitative assessment. Initial experimental results are demonstrated on mercurous chloride samples.

Interpolation methods for the improvement of the point spread function estimation

  • DOI: 10.1109/RADIOELEK.2018.8376375
  • Link: https://doi.org/10.1109/RADIOELEK.2018.8376375
  • Department: Department of Radioelectronics
  • Annotation:
    Interpolation methods face the issue of the specific content of the images. This paper is devoted to a comparison of interpolation methods suitable for small image content and its influence on improvement in the PSF estimation. The issue is that when the PSF is represented by only several pixels, the model of the system is not correctly optimized. Selection of the suitable interpolation method represents the main aim with consequences to the PSF model estimation.

Photometric analysis of globular clusters using modified Richardson–Lucy algorithm—comparison with DAOPHOT

  • Authors: Blažek, M., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Astronomische Nachrichten. 2018, 339(5), 371-374. ISSN 0004-6337.
  • Year: 2018
  • DOI: 10.1002/asna.201813508
  • Link: https://doi.org/10.1002/asna.201813508
  • Department: Department of Radioelectronics
  • Annotation:
    In this paper, we show the comparison tests of a standard DAOPHOT photometric algorithm with new WHIDE method based on Richardson–Lucy deconvolution for the case of globular stellar cluster cores where the overlapping signal from nearby bright stars hides the fainter stars. Tests are performed on the globular clusters M53 ((V−R) color–magnitude diagram) and M92 (astrometric stellar positions).

The THESEUS space mission concept: science case, design and expected performances

  • DOI: 10.1016/j.asr.2018.03.010
  • Link: https://doi.org/10.1016/j.asr.2018.03.010
  • Department: Department of Radioelectronics
  • Annotation:
    THESEUS is a space mission concept aimed at exploiting Gamma-Ray Bursts for investigating the early Universe and at providing a substantial advancement of multi-messenger and time-domain astrophysics. These goals will be achieved through a unique combination of instruments allowing GRB and X-ray transient detection over a broad field of view (more than 1 sr) with 0.5-1 arcmin localization, an energy band extending from several MeV down to 0.3 keV and high sensitivity to transient sources in the soft X-ray domain, as well as on-board prompt (few minutes) follow-up with a 0.7 m class IR telescope with both imaging and spectroscopic capabilities. THESEUS will be perfectly suited for addressing the main open issues in cosmology such as, e.g., star formation rate and metallicity evolution of the inter-stellar and intra-galactic medium up to redshift similar to 10, signatures of Pop III stars, sources and physics of re-ionization, and the faint end of the galaxy luminosity function. In addition, it will provide unprecedented capability to monitor the X-ray variable sky, thus detecting, localizing, and identifying the electromagnetic counterparts to sources of gravitational radiation, which may be routinely detected in the late '20s/early '30s by next generation facilities like aLIGO/ aVirgo, eLISA, KAGRA, and Einstein Telescope. THESEUS will also provide powerful synergies with the next generation of multi-wavelength observatories (e.g., LSST, ELT, SKA, CTA, ATHENA). (C) 2018 COSPAR. Published by Elsevier Ltd. All rights reserved.

Toward astrometric calibration of ultrawide‐field images

  • DOI: 10.1002/asna.201813514
  • Link: https://doi.org/10.1002/asna.201813514
  • Department: Department of Radioelectronics
  • Annotation:
    In this paper, we introduce a new method of astrometric calibration tailored especially for ultrawide‐field systems like WILLIAM. The standard astrometric solution often fails to provide any result if the processed image contains a large amount of distortion, such as from a fisheye lens. Some algorithms yield the result, but the accuracy is satisfactory only at the center of the field of view. This work analyzes such images and proposes a new method that leads to much higher accuracy and success ratio of the calibration.

Astronomical Tasks for Tests of X-Ray Optics in VZLUSAT-1 Nanosatellite

  • Authors: Blažek, M., prof. Mgr. Petr Páta, Ph.D., Inneman, A., Skala, P.
  • Publication: Advances in Astronomy. 2017, 2017 ISSN 1687-7969.
  • Year: 2017
  • DOI: 10.1155/2017/3162892
  • Link: https://doi.org/10.1155/2017/3162892
  • Department: Department of Radioelectronics
  • Annotation:
    VZLUSAT-1 nanosatellite (scheduled launch in spring 2017 from India) is a CubeSat mission which, besides other instrumentation, contains X-ray desk to perform efficiency tests of the X-ray optics. In this article the analysis of potential observational candidates for VZLUSAT-1 X-ray board is presented together with the suggestion of observational modes, laboratory measurements, and estimations of exposure settings.

New generation of meteorology cameras

  • Authors: Janout, P., Blažek, M., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Proc. SPIE 10603, Photonics, Devices, and Systems VII. Bellingham (stát Washington): SPIE, 2017. Proceedings of SPIE. vol. 10603. ISSN 0277-786X. ISBN 978-1-5106-1702-5.
  • Year: 2017
  • DOI: 10.1117/12.2296846
  • Link: https://doi.org/10.1117/12.2296846
  • Department: Department of Radioelectronics
  • Annotation:
    A new generation of the WILLIAM (WIde-field aLL-sky Image Analyzing Monitoring system) camera includes new features such as monitoring of rain and storm clouds during the day observation. Development of the new generation of weather monitoring cameras responds to the demand for monitoring of sudden weather changes. However, new WILLIAM cameras are ready to process acquired image data immediately, release warning against sudden torrential rains, and send it to user's cell phone and email. Actual weather conditions are determined from image data, and results of image processing are complemented by data from sensors of temperature, humidity, and atmospheric pressure. In this paper, we present the architecture, image data processing algorithms of mentioned monitoring camera and spatially-variant model of imaging system aberrations based on Zernike polynomials.

Pole searching algorithm for Wide-field all-sky image analyzing monitoring system

  • Department: Department of Radioelectronics
  • Annotation:
    Paper show how to find coordinates of the celestial pole. The algorithm is useful as the first hint for blind astrometry in order to help or speed up the process. The algorithm uses a principle of Hough transformation commonly used in computer vision.

PSF Estimation of Space-Variant Ultra-Wide Field of View Imaging Systems

  • DOI: 10.3390/app7020151
  • Link: https://doi.org/10.3390/app7020151
  • Department: Department of Radioelectronics
  • Annotation:
    Ultra-wide-field of view (UWFOV) imaging systems are affected by various aberrations, most of which are highly angle-dependent. A description of UWFOV imaging systems, such as microscopy optics, security camera systems and other special space-variant imaging systems, is a difficult task that can be achieved by estimating the Point Spread Function (PSF) of the system. This paper proposes a novel method for modeling the space-variant PSF of an imaging system using the Zernike polynomials wavefront description. The PSF estimation algorithm is based on obtaining field-dependent expansion coefficients of the Zernike polynomials by fitting real image data of the analyzed imaging system using an iterative approach in an initial estimate of the fitting parameters to ensure convergence robustness. The method is promising as an alternative to the standard approach based on Shack-Hartmann interferometry, since the estimate of the aberration coefficients is processed directly in the image plane. This approach is tested on simulated and laboratory-acquired image data that generally show good agreement. The resulting data are compared with the results of other modeling methods. The proposed PSF estimation method provides around 5% accuracy of the optical system model.

Resolution analysis of archive films for the purpose of their optimal digitization and distribution

  • DOI: 10.1117/12.2274095
  • Link: https://doi.org/10.1117/12.2274095
  • Department: Department of Radioelectronics
  • Annotation:
    With recent high demand for ultra-high-definition (UHD) content to be screened in high-end digital movie theaters but also in the home environment, film archives full of movies in high-definition and above are in the scope of UHD content providers. Movies captured with the traditional film technology represent a virtually unlimited source of UHD content. The goal to maintain complete image information is also related to the choice of scanning resolution and spatial resolution for further distribution. It might seem that scanning the film material in the highest possible resolution using state-of-the-art film scanners and also its distribution in this resolution is the right choice. The information content of the digitized images is however limited, and various degradations moreover lead to its further reduction. Digital distribution of the content in the highest image resolution might be therefore unnecessary or uneconomical. In other cases, the highest possible resolution is inevitable if we want to preserve fine scene details or film grain structure for archiving purposes. This paper deals with the image detail content analysis of archive film records. The resolution limit in captured scene image and factors which lower the final resolution are discussed. Methods are proposed to determine the spatial details of the film picture based on the analysis of its digitized image data. These procedures allow determining recommendations for optimal distribution of digitized video content intended for various display devices with lower resolutions. Obtained results are illustrated on spatial downsampling use case scenario, and performance evaluation of the proposed techniques is presented.

Set of Methodologies for Archive Film Digitization and Restoration with Examples of Their Application in ORWO Region

  • DOI: 10.2352/issn.2168-3204.2017.1.0.62
  • Link: https://doi.org/10.2352/issn.2168-3204.2017.1.0.62
  • Department: Department of Radioelectronics
  • Annotation:
    In this paper; we present a set of verified methodologies suitable for application to a particular problem of archive films' restoration and digitization, especially when a nonstandard laboratory or creative techniques were used, which is typical for so-called ORWO region. The umbrella of the presented techniques is formed by established Digitally Restored Authorizate (DRA) methodology, with its aim to achieve the appearance of the audio and visual components of the digitized film as close as possible to the original author's concept. Among the methodologies, we present tools for objective assessment of perceived differences in the outcomes of the color grading process. These techniques are suitable for evaluation of appearance match among various available versions of the digitized film in respect to the DRA outcome.

A Decade of GRB Follow-Up by BOOTES in Spain (2003–2013)

  • Authors: Jelínek, M., Castro-Tirado, A. J., Cunniffe, R., Gorosabel, J., doc. Ing. Stanislav Vítek, Ph.D., Kubánek, P., de Ugarte Postigo, A., Guziy, S., Tello, J. C., prof. Mgr. Petr Páta, Ph.D., Sánchez-Ramírez, R., Oates, S., Jeong, S,, Štrobl, J., Castillo-Carrión, S., Sanguino, T. M., Rabaza, O., Pérez-Ramírez, D., Fernández-Muñoz, R., de la Morena Carretero, B. A., prof. RNDr. René Hudec, CSc., Reglero, V., Sabau-Graziati, L.
  • Publication: Advances in Astronomy. 2016, 2016 ISSN 1687-7969.
  • Year: 2016
  • DOI: 10.1155/2016/1928465
  • Link: https://doi.org/10.1155/2016/1928465
  • Department: Department of Radioelectronics
  • Annotation:
    This article covers ten years of GRB follow-ups by the Spanish BOOTES stations: 71 follow-ups providing 23 detections. Follow-ups by BOOTES-1B from 2005 to 2008 were given in a previous article and are here reviewed and updated, and additional detection data points are included as the former article merely stated their existence. The all-sky cameras CASSANDRA have not yet detected any GRB optical afterglows, but limits are reported where available.

Application of field dependent polynomial model

  • DOI: 10.1117/12.2237310
  • Link: https://doi.org/10.1117/12.2237310
  • Department: Department of Radioelectronics
  • Annotation:
    Extremely wide-field imaging systems have many advantages regarding large display scenes whether for use in microscopy, all sky cameras, or in security technologies. The Large viewing angle is paid by the amount of aberrations, which are included with these imaging systems. Modeling wavefront aberrations using the Zernike polynomials is known a longer time and is widely used. Our method does not model system aberrations in a way of modeling wavefront, but directly modeling of aberration Point Spread Function of used imaging system. This is a very complicated task, and with conventional methods, it was difficult to achieve the desired accuracy. Our optimization techniques of searching coefficients space-variant Zernike polynomials can be described as a comprehensive model for ultra-wide-field imaging systems. The advantage of this model is that the model describes the whole space-variant system, unlike the majority models which are partly invariant systems. The issue that this model is the attempt to equalize the size of the modeled Point Spread Function, which is comparable to the pixel size. Issues associated with sampling, pixel size, pixel sensitivity profile must be taken into account in the design. The model was verified in a series of laboratory test patterns, test images of laboratory light sources and consequently on real images obtained by an extremely wide-field imaging system WILLIAM. Results of modeling of this system are listed in this article.

Evaluation of color grading impact in restoration process of archive films

  • DOI: 10.1117/12.2237558
  • Link: https://doi.org/10.1117/12.2237558
  • Department: Department of Radioelectronics
  • Annotation:
    Color grading of archive films is a very particular task in the process of their restoration. The ultimate goal of color grading here is to achieve the same look of the movie as intended at the time of its first presentation. The role of the expert restorer, expert group and a digital colorist in this complicated process is to find the optimal settings of the digital color grading system so that the resulting image look is as close as possible to the estimate of the original reference release print adjusted by the expert group of cinematographers. A methodology for subjective assessment of perceived differences between the outcomes of color grading is introduced, and results of a subjective study are presented. Techniques for objective assessment of perceived differences are discussed, and their performance is evaluated using ground truth obtained from the subjective experiment. In particular, a solution based on calibrated digital single-lens reflex camera and subsequent analysis of image features captured from the projection screen is described. The system based on our previous work is further developed so that it can be used for the analysis of projected images. It allows assessing color differences in these images and predict their impact on the perceived difference in image look.

Image processing of Globular Clusters - Simulation for Deconvolution Tests (GlencoeSim)

  • DOI: 10.1016/j.newast.2016.04.001
  • Link: https://doi.org/10.1016/j.newast.2016.04.001
  • Department: Department of Radioelectronics
  • Annotation:
    This paper presents an algorithmic approach for efficiency tests of deconvolution algorithms in astronomic image processing. Due to the existence of noise in astronomical data there is no certainty that a mathematically exact result of stellar deconvolution exists and iterative or other methods such as aperture or PSF fitting photometry are commonly used. Iterative methods are important namely in the case of crowded fields (e.g., globular clusters). For tests of the efficiency of these iterative methods on various stellar fields, information about the real fluxes of the sources is essential. For this purpose a simulator of artificial images with crowded stellar fields provides initial information on source fluxes for a robust statistical comparison of various deconvolution methods. The ”GlencoeSim” simulator and the algorithms presented in this paper consider various settings of Point-Spread Functions, noise types and spatial distributions, with the aim of producing as realistic an astronomical optical stellar image as possible.

Live film: Film digitalization by DRA Method

  • Authors: Černíček, J., Ing. Karel Fliegel, Ph.D., Folvarčný, J., Frouz, M., Fuxjager, K., Gloc, J., Hendrich, V., Hubička, J., Hyťha, L., Jakubisko, J., Mathé, I., Menzel, J., Michalovič, P., Myslík, P., Novák, M., Novotný, J., prof. Mgr. Petr Páta, Ph.D., Pecák, J., Piškula, M., Rejholec, P., Savický, N., Souček, D., Stuchlík, Z., Šimunek, J., Štoll, M., doc. Ing. Stanislav Vítek, Ph.D., Weigl, P., Weiser, A., Winston, B., Zuska, V.
  • Publication: Praha: Lepton studio, 2016. ISBN 978-80-904503-4-9.
  • Year: 2016
  • Department: Department of Radioelectronics
  • Annotation:
    The book summarizes process of digitalization of national movie fund and results of five years of a research project of finding the digitalization methodology in frame of NAKI programme. It introduces the method of Digital Restored Authorizate (DRA) and the evolution of digitalization process in the Czech Republic in the last decade.

Localization and broadband follow-up of the gravitational-wave transient GW150914

  • DOI: 10.3847/2041-8205/826/1/L13
  • Link: https://doi.org/10.3847/2041-8205/826/1/L13
  • Department: Department of Radioelectronics
  • Annotation:
    A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams.

Long-Term Continuous Double Station Observation of Faint Meteor Showers

  • DOI: 10.3390/s16091493
  • Link: https://doi.org/10.3390/s16091493
  • Department: Department of Radioelectronics
  • Annotation:
    Meteor detection and analysis is an essential topic in the field of astronomy. In this paper, a high-sensitivity and high-time-resolution imaging device for the detection of faint meteoric events is presented. The instrument is based on a fast CCD camera and an image intensifier. Two such instruments form a double-station observation network. The MAIA (Meteor Automatic Imager and Analyzer) system has been in continuous operation since 2013 and has successfully captured hundreds of meteors belonging to different meteor showers, as well as sporadic meteors. A data processing pipeline for the efficient processing and evaluation of the massive amount of video sequences is also introduced in this paper.

Realization of High Dynamic Range Imaging in the GLORIA Network and Its Effect on Astronomical Measurement

  • DOI: 10.1155/2016/8645650
  • Link: https://doi.org/10.1155/2016/8645650
  • Department: Department of Radioelectronics
  • Annotation:
    Citizen science project GLORIA (GLObal Robotic-telescopes Intelligent Array) is a first free- and open-access network of robotic telescopes in the world. It provides a web-based environment where users can do research in astronomy by observing with robotic telescopes and/or by analyzing data that other users have acquired with GLORIA or from other free-access databases. Network of 17 telescopes allows users to control selected telescopes in real time or schedule any more demanding observation. This paper deals with new opportunity that GLORIA project provides to teachers and students of various levels of education. At the moment, there are prepared educational materials related to events like Sun eclipse (measuring local atmosphere changes), Aurora Borealis (calculation of Northern Lights height), or transit of Venus (measurement of the Earth-Sun distance). Student should be able to learn principles of CCD imaging, spectral analysis, basic calibration like dark frames subtraction, or advanced methods of noise suppression. Every user of the network can design his own experiment. We propose advanced experiment aimed at obtaining astronomical image data with high dynamic range. We also introduce methods of objective image quality evaluation in order to discover how HDR methods are affecting astronomical measurements.

Simultaneous analogue and digital observations and comparison of results

  • Department: Department of Radioelectronics
  • Annotation:
    Double station observations using analogue video cameras are carried out at the Ondřejov observatory since 1998. Recently new digital cameras MAIA were developed and introduced. Both systems are based on the same type of image intensifier. To evaluate the enhanced properties of the new cameras several simultaneous campaigns with both systems were accomplished.

SUPPLEMENT: "LOCALIZATION AND BROADBAND FOLLOW-UP OF THE GRAVITATIONAL-WAVE TRANSIENT GW150914" (2016, ApJL, 826, L13)

  • DOI: 10.3847/0067-0049/225/1/8
  • Link: https://doi.org/10.3847/0067-0049/225/1/8
  • Department: Department of Radioelectronics
  • Annotation:
    This Supplement provides supporting material for Abbott et al. (2016a). We briefly summarize past electromagnetic (EM) follow-up efforts as well as the organization and policy of the current EM follow-up program. We compare the four probability sky maps produced for the gravitational-wave transient GW150914, and provide additional details of the EM follow-up observations that were performed in the different bands.

Astronomical Context Coder for Image Compression

  • Authors: prof. Mgr. Petr Páta, Ph.D., Schindler, J.
  • Publication: EXPERIMENTAL ASTRONOMY. 2015, 39(3), 495-512. ISSN 0922-6435.
  • Year: 2015
  • DOI: 10.1007/s10686-015-9460-3
  • Link: https://doi.org/10.1007/s10686-015-9460-3
  • Department: Department of Radioelectronics
  • Annotation:
    Recent lossless still image compression formats are powerful tools for compression of all kind of common images (pictures, text, schemes, etc.). Generally, the performance of a compression algorithm depends on its ability to anticipate the image function of the processed image. In other words, a compression algorithm to be successful, it has to take perfectly the advantage of coded image properties. Astronomical data form a special class of images and they have, among general image properties, also some specific characteristics which are unique [1]. If a new coder is able to correctly use the knowledge of these special properties it should lead to its superior performance on this specific class of images at least in terms of the compression ratio. In this work, the novel lossless astronomical image data compression method will be presented. The achievable compression ratio of this new coder will be compared to theoretical lossless compression limit and also to the recent compression standards of the astronomy and general multimedia.

Colour transformations and K-means segmentation for automatic cloud detection

  • Authors: Blažek, M., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Meteorologische Zeitschrift. 2015, 24(5), 503-509. ISSN 0941-2948.
  • Year: 2015
  • DOI: 10.1127/metz/2015/0656
  • Link: https://doi.org/10.1127/metz/2015/0656
  • Department: Department of Radioelectronics
  • Annotation:
    The main aim of this work is to find simple criteria for automatic recognition of several meteorological phenomena using optical digital sensors (e.g., Wide-Field cameras, automatic DSLR cameras or robotic telescopes). The output of those sensors is commonly represented in RGB channels containing information about both colour and luminosity even when normalised. Transformation into other colour spaces (e.g., CIE 1931 xyz, CIE L*a*b*, YCbCr) can separate colour from luminosity, which is especially useful in the image processing of automatic cloud boundary recognition. Different colour transformations provide different sectorization of cloudy images. Hence, the analysed meteorological phenomena (cloud types, clear sky) project differently into the colour diagrams of each international colour systems. In such diagrams, statistical tools can be applied in search of criteria which could determine clear sky from a covered one and possibly even perform a meteorological classification of cloud types. For the purpose of this work, a database of sky images (both clear and cloudy), with emphasis on a variety of different observation conditions (e.g., time, altitude, solar angle, etc.) was acquired. The effectiveness of several colour transformations for meteorological application is discussed and the representation of different clouds (or clear sky) in those colour systems is analysed. Utilisation of this algorithm would be useful in all-sky surveys, supplementary meteorological observations, solar cell effectiveness predictions or daytime astronomical solar observations.

GPU accelerated processing of astronomical high frame-rate videosequences

  • DOI: 10.1117/12.2188610
  • Link: https://doi.org/10.1117/12.2188610
  • Department: Department of Radioelectronics
  • Annotation:
    Astronomical instruments located around the world are producing an incredibly large amount of possibly interesting scientific data. Astronomical research is expanding into large and highly sensitive telescopes. Total volume of data rates per night of operations also increases with the quality and resolution of state-of-the-art CCD/CMOS detectors. Since many of the ground-based astronomical experiments are placed in remote locations with limited access to the Internet, it is necessary to solve the problem of the data storage. It mostly means that current data acquistion, processing and analyses algorithm require review. Decision about importance of the data has to be taken in very short time. This work deals with GPU accelerated processing of high frame-rate astronomical video-sequences, mostly originating from experiment MAIA (Meteor Automatic Imager and Analyser), an instrument primarily focused to observing of faint meteoric events with a high time resolution. The instrument with price bellow 2000 euro consists of image intensifier and gigabite ethernet camera running at 61 fps. With resolution better than VGA the system produces up to 2TB of scientifically valuable video data per night. Main goal of the paper is not to optimize any GPU algorithm, but to propose and evaluate parallel GPU algorithms able to process huge amount of video-sequences in order to delete all uninteresting data.

Measurement of ultra wide-field imaging systems

  • Department: Department of Radioelectronics
  • Annotation:
    Measurement of parameters of ultra-wide imaging systems is a problematic task, both in terms of correct measurement arrangement, and in terms of the evaluation results. Wide-angle lenses used in such as systems, which include lenses known as fish-eye, have a field of view up to 180 degrees in the circular lenses or 160° for diagonal fisheye lenses. Lenses with such a wide field of view suffers from several optical defects such as distortion, chromatic aberration or uneven lighting scenes. Particular attention should be paid to image quality. In many applications, such as security cameras, astronomical cameras and other, the required uniformity of the image in the entire field of view because the entire field of view may contain important details. Like less extreme lens is one aspect of how to assess the quality of the display measuring MTF (Modulation Transfer Function) and resolution. Measurement of these characteristics in a wide-angle lens brings new challenges and it is necessary to adapt the measuring methods distorting lens properties. This article deals with precisely measuring the MTF, resolution and chromatic aberration, so that the results reflect an unusual depiction of the scene.

OFT Sectorization Approach to Analysis of Optical Scattering in Mercurous Chloride Single Crystals

  • DOI: 10.1364/OE.23.021509
  • Link: https://doi.org/10.1364/OE.23.021509
  • Department: Department of Radioelectronics
  • Annotation:
    The paper is devoted to the application of the optical Fourier transform (OFT) to the study and evaluation of optical scattering in the latest generation of calomel single crystals ready for application in several possible devices such as IR polarizers and acoustooptic tunable filters (AOTF). There are numerous effects that are responsible for the scattering of an optical wave passing through the crystal sample volume and surface layers, and they affect the optical crystal quality. The scattering level is a crucial and limiting parameter in many technical applications of an evaluated crystal. The proposed approach is based upon the high dynamic range optical FT configuration, creating the amplitude spectrum in the focal plane and its spatial angular distribution analysis based on the spectrum sectorization. The optical scattering pattern was tested in nine locations within each crystal sample volume and on numerous crystal samples. The experimental results are presented and discussed.

Optical Fourier transform

  • Department: Department of Radioelectronics
  • Annotation:
    In various fields of image processing we can currently meet with use of the Fourier transform either within processing of one-dimensional signals or working with multi-dimensional signals as are for example images. Signal transformation can be described by any expression of the Fourier transform - discrete Fourier transform (DFT), short-term Fourier transform (STFT), but each time it is implemented by the algorithm of fast Fourier transform in the case of digital input data. Another alternative is presenting itself for image processing - direct use of optics. The Fourier transform of the image is carried out directly by the optical system. Low-pass and high-pass filtration can be simply carried out this way. This article presents one of the possible derivations of the optical Fourier transform (OFT) principle. Setup used for OFT and space filtration is shown together with typical visual patterns and their spectra shapes before and after filtration.

Performance evaluation of image deconvolution techniques in space-variant astronomical imaging systems with nonlinearities

  • DOI: 10.1117/12.2187888
  • Link: https://doi.org/10.1117/12.2187888
  • Department: Department of Cybernetics, Department of Radioelectronics
  • Annotation:
    There are various deconvolution methods for suppression of blur in images. In this paper a survey of image deconvolution techniques is presented with focus on methods designed to handle images acquired with wide-field astronomical imaging systems. Image blur present in such images is space-variant especially due to space-variant point spread function (PSF) of the lens. The imaging system can contain also nonlinear electro-optical elements. Analysis of nonlinear and space-variant imaging systems is usually simplified so that the system is considered as linear and space-invariant (LSI) under specific constraints. Performance analysis of selected image deconvolution methods is presented in this paper, while considering space-variant nature of wide-field astronomical imaging system. Impact of nonlinearity on the overall performance of image deconvolution technique is also analyzed. Test images with characteristics obtained from the real system with space-variant wide-field input lens and nonlinear image intensifier are used for the performance analysis.

Stellar objects identification using wide-field camera

  • Authors: Janout, P., prof. Mgr. Petr Páta, Ph.D., Ing. Jan Bednář, Ph.D., Anisimova, E., Blažek, M., Skala, P.
  • Publication: Proc. SPIE 9450, Photonics, Devices, and Systems VI. Bellingham: SPIE, 2015. p. 94501I-1-94501I-9. Proceedings of SPIE. ISSN 0277-786X. ISBN 978-1-62841-566-7.
  • Year: 2015
  • DOI: 10.1117/12.2074255
  • Link: https://doi.org/10.1117/12.2074255
  • Department: Department of Radioelectronics
  • Annotation:
    This paper deals with evaluation and processing of astronomical image data, which are obtained by a wide- field all-sky image analyzing monitoring system (WILLIAM). The WILLIAM is an additional experimental camera for project MAIA equipped with wide-field lens. The system can detect stellar objects as faint as 6th magnitude. Acquired image data are processed by an algorithm for stellar object detection and identification which is based on coordinates transfer function. Cartesian coordinates at the image data are transformed to horizontal coordinate system. This coordinate system allows searching in astronomical catalogues of stellar objects. This paper presents the components of WILLIAM, its measured electro-optical characteristics and some results of identification.

The Impact of KLT Coder on the Image Distortion in Astronomy

  • DOI: 10.1155/2015/484379
  • Link: https://doi.org/10.1155/2015/484379
  • Department: Department of Radioelectronics
  • Annotation:
    Presented paper is devoted to the application of Karhunen-Loève transform (KLT) for compression and to study of KLT impact on the image distortion in astronomy. This transform is an optimal fit for images with Gaussian probability density function in order to minimize the root mean square error (RMSE). The main part of the encoder is proposed in relation to statistical image properties. Selected astronomical image processing algorithms are used for the encoder testing. The astrometry and point spread function distortion are selected as the most important criteria. The results are compared with JPEG2000 standard. The KLT encoder provides better results from the RMSE point of view. These results are promising and show the novel approach to the design of lossy image compression algorithms and also suitability for algorithms of image data structuring for retrieving, transfer, and distribution.

All-sky camera with extreme wide-field of view

  • Authors: Janout, P., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Jemná mechanika a optika. 2014, 59(10), 281-283. ISSN 0447-6441.
  • Year: 2014
  • Department: Department of Radioelectronics
  • Annotation:
    WILLIAM stands for a wide-field all-sky image analysing monitoring system. This stand-alone system, based on algorithms for detection of star objects, can monitor the night sky and then evaluate the weather conditions suitable for star observation. The system employs the single lens reflection (SLR) camera with fish-eye lens. By the means of processing of night sky frames one can decide whether conditions are suitable for star telescopy. Identifiaction of vidible stars is a consequence of frames processing using the database system WILLIAM.

Correction of lens distortion for astronomical plates digitized by SLR camera

  • Authors: Anisimova, E., prof. Mgr. Petr Páta, Ph.D., Del Campo, M.
  • Publication: Astroplate 2014. Praha: VŠCHT, 2014. pp. 123-126. ISBN 978-80-7080-918-1.
  • Year: 2014
  • Department: Department of Radioelectronics
  • Annotation:
    It is necessary to carry out precise measurement of detected stellar objects in astronomy. In case of astronomical plates digitization by digital SLR (Single Lens Reflection) camera, they could be trans-illuminated and taken by the camera equipped with a suitable lens. The condition is a 100% match of an object (astronomical plate) and its image. Nevertheless, mentioned imaging system is not ideal. Various optical aberrations occur during acquisition. They introduce errors as are e.g. distortion, coma, astigmatism or chromatic aberration. Distor- tion influences correct positions of stellar objects and causes incorrect interpretation of taken data whether they were correct acquired using astronomical plate. Therefore, it is necessary to modify existing methods for astronomical image processing in the case of input lens with wider field of view or to remove lens distortion and apply existing algorithms. In this paper we describe a principle of image system distortion elimination using OpenCV software library.

Estimation and measurement of space-variant features of imaging systems and influence of this knowledge on accuracy of astronomical measurement

  • DOI: 10.1117/12.2061736
  • Link: https://doi.org/10.1117/12.2061736
  • Department: Department of Radioelectronics
  • Annotation:
    Additional monitoring equipment is commonly used in astronomical imaging. This electro-optical system usually complements the main telescope during acquisition of astronomical phenomena or supports its operation e.g. evaluating the weather conditions. Typically it is a wide-field imaging system, which consists of a digital camera equipped with fish-eye lens. The wide-field imaging system cannot be considered as a space-invariant because of space-variant nature of its input lens. In our previous research efforts we have focused on measurement and analysis of images obtained from the subsidiary all-sky monitor WILLIAM (WIde-field aLL-sky Images Analyzing Monitoring system). Space-variant part of this imaging system consists of input lens with 180 fi angle of view in horizontal and 154 fi in vertical direction. For a precise astronomical measurement over the entire field of view, it is very important to know how the optical aberrations affect characteristics of the imaging system, especially its PSF (Point Spread Function). Two methods were used for characterization of the space-variant PSF, i.e. measurement in the optical laboratory and estimation using acquired images and Zernike polynomials. Analysis of results obtained using these two methods is presented in the paper. Accuracy of astronomical measurements is also discussed while considering the space-variant PSF of the system.

Segmentation of astronomical images

  • DOI: 10.1117/12.2062009
  • Link: https://doi.org/10.1117/12.2062009
  • Department: Department of Radioelectronics
  • Annotation:
    Object detection is one of the most important procedures in astronomical imaging. This paper deals with segmentation of astronomical images based on random forrest classifier. We consider astronomical image data acquired using a photometric system with B, V, R and I filters. Each image is acquired in more realizations. All image realizations are corrected using master dark frame and master flat field obtained as an average of hundreds of images. Then a profile photometry is applied to find possible position of stars. The classifier is trained by B, V, R and I image vectors. Training samples are defined by user using ellipsoidal regions (20 selections for both classes: object, background). A number of objects and their positions are compared with astronomical object catalogue using Euclidean distance. We can conclude that the performance of the presented technique is fully comparable to other SoA algorithms.

System for objective assessment of image differences in digital cinema

  • Authors: Ing. Karel Fliegel, Ph.D., Krasula, L., prof. Mgr. Petr Páta, Ph.D., Myslík, J., Pecák, J., Jícha, M.
  • Publication: Applications of Digital Image Processing XXXVII. Bellingham: SPIE, 2014. pp. 92170I-1-92170I-14. Proceedings of SPIE. ISSN 0277-786X. ISBN 978-1-62841-244-4.
  • Year: 2014
  • DOI: 10.1117/12.2061016
  • Link: https://doi.org/10.1117/12.2061016
  • Department: Department of Radioelectronics
  • Annotation:
    There is high demand for quick digitization and subsequent image restoration of archived film records. Digitization is very urgent in many cases because various invaluable pieces of cultural heritage are stored on aging media. Only selected records can be reconstructed perfectly using painstaking manual or semi-automatic procedures. This paper aims to answer the question what are the quality requirements on the restoration process in order to obtain acceptably close visual perception of the digitally restored film in comparison to the original analog film copy. This knowledge is very important to preserve the original artistic intention of the movie producers. Subjective experiment with artificially distorted images has been conducted in order to answer the question what is the visual impact of common image distortions in digital cinema. Typical color and contrast distortions were introduced and test images were presented to viewers using digital projector. Based on the outcome of this subjective evaluation a system for objective assessment of image distortions has been developed and its performance tested. The system utilizes calibrated digital single-lens reflex camera and subsequent analysis of suitable features of images captured from the projection screen. The evaluation of captured image data has been optimized in order to obtain predicted differences between the reference and distorted images while achieving high correlation with the results of subjective assessment. The system can be used to objectively determine the difference between analog film and digital cinema images on the projection screen.

The GLObal Robotic telescopes Intelligent Array for E-Science (GLORIA)

  • Authors: Castro-Tirado, A.J., Sánchez Moreno, F.M., Pérez del Pulgar, C., Azócar, D., Beskin, G., Cabello, J., Cedazo, R., Cuesta, L., Cunniffe, R., Gonzáles, E., Gonzáles-Rodríguez, A., Gorosabel, J., Hanlon, L., prof. RNDr. René Hudec, CSc., Jakubek, M., Janeček, P., Jelínek, M., Lara-Gil, O., Linttot, C., López-Casado, M.C., Malaspina, M., Mankiewicz, L., Maureira, E., Maza, J., Muñoz-Martínez, V.F., Nicastro, L., O'Boyle, E., Palazzi, E., prof. Mgr. Petr Páta, Ph.D. Pio, M.A., Prouza, M., Serena, F., Serra-Ricart, M., Simpson, R., Sprimont, P., Strobl, J., Topinka, M., doc. Ing. Stanislav Vítek, Ph.D. Zarnecki, A.F.
  • Publication: III Workshop on Robotic Autonomous Observatories. México: Universidad Nacional Autónoma de México, 2014. p. 104-109. Revista Mexicana de Astronomia y Astrofisica-Serie de Conferencias. ISSN 1405-2059.
  • Year: 2014
  • Department: Department of Radioelectronics
  • Annotation:
    GLORIA is a collaborative web-2.0 project based on a network of robotic telescopes, which has become the first free-access network opened to the world for public outreach and specially for e-Science projects.

Analysis of images obtained from space-variant astronomical imaging systems

  • DOI: 10.1117/12.2023904
  • Link: https://doi.org/10.1117/12.2023904
  • Department: Department of Radioelectronics
  • Annotation:
    Most of the classical approaches to the measurement and modeling of electro-optical imaging systems rely on the principles of linearity and space invariance (LSI). In our previous research efforts we have focused on measurement and analysis of images obtained from a double station video observation system MAIA (Meteor Automatic Imager and Analyzer). The video acquisition module of this system contains wide-field input lens which contributes to space-variability of the imaging system. For a precise astronomical measurement over the entire field of view, it is very important to comprehend how the characteristics of the imaging system can affect astrometric and photometric outputs. This paper presents an analysis of how the space-variance of the imaging system can affect precision of astrometric and photometric results. This analysis is based on image data acquired in laboratory experiments and astronomical observations with the wide-field system. Methods for efficient calibration of this system to obtain precise astrometric and photometric measurements are also proposed.

Astronomical Image Denoising using Curvelet and Starlet Transform

  • DOI: 10.1109/RadioElek.2013.6530927
  • Link: https://doi.org/10.1109/RadioElek.2013.6530927
  • Department: Department of Radioelectronics
  • Annotation:
    Astronomical image data acquisition under low light conditions causes higher noise occurrence in these data. There are a lot of noise sources including also the thermally generated noise (dark current) inside used astronomical CCD sensor and the Poisson noise of the photon flux. There are specific image quality criteria in astronomy. These criteria are derived from the algorithms for astronomical image processing and are specific in the field of multimedia signal processing. Astrometric and photometric algorithms provide information about stellar objects: their brightness profile (PSF), position and magnitude. They could fail because of lower SNR. This problem can be solved by subtraction a dark frame from a captured image nowadays. However, this method couldn't work properly in systems with shorter shutter speed and nonlinear sensitivity, such as for example the system MAIA (Meteor Automatic Imager and Analyser). Image data from these system could not been processed by conventional algorithms. Denoising of the astronomical images is therefore still a big challenge for astronomers and people who process astronomical data. Therefore new algorithms are proposed in this paper. We describe our experiences with astronomical image data denoising based on Curvelet and Starlet transform. Novel algorithms have been tested on image data from MAIA system. Their influence on the stellar object detecting algorithms and on important photometric data like stellar magnitude and FWHM (Full Width at Half Maximum) has been studied and compared with conventional denoising methods.

Efficiency of Wavelet Coefficients Thresholding Techniques used for Multimedia and Astronomical Image Denoising

  • Department: Department of Radioelectronics
  • Annotation:
    This paper deals with image denoising based on the wavelet transform realized by Mallat algorithm and À trous algorithm. The effectiveness of global and subband thresholding techniques are studied on multimedia and astronomical images contaminated by Gaussian noise. Experimental results on several testing images are compared with each other from two objective quality aspects (PSNR, RMSE). Astronomical image denoising techniques differ from those used for multimedia images, because astronomical data are processed by computers and are not evaluated by humans. Thus we show especially the difference between quality criteria related with both types of images after denoising. In case of astronomical data, important scientific criteria as stellar magnitude and FWHM (Full Width at Half Maximum) changes are studied in processed images after noise removal.

Image processing using the wavelet transform

  • Department: Department of Radioelectronics
  • Annotation:
    Authors of this paper summarized properties of the wavelet transform in such a way, that there were derived reasons for its usage in an area of both 1D and 2D signal processing and analysis, starting with noise suppression, through signal coding and sharpening up to object detection. Authors tried to explain the issue in the most understandable way, involving a large number of verbal explanation and comprehensive figures.

The Point Spread Function Variations inside Wide-field Astonomical Images

  • Department: Department of Radioelectronics
  • Annotation:
    The Point Spread Function (PSF) of the astronomical imaging system is usually approximated by a Gaussian or Moffat function. For simplification, the astronomical imaging system is considered to be time and space invariant. This means that invariable PSF within an exposed image is assumed. If real wide-field imaging systems are considered, this presumption is not fulfilled. In real systems, stronger optical aberrations are expected (especially coma) at greater distances from the center of the captured image. This impacts the efficiency of stellar astrometry and photometry algorithms, so it is necessary to know the PSF variation. In this paper, we perform the first step toward assigning PSF changes: we study the dependence of the Moffat function fitting parameters (FWHM and the atmospheric scattering coefficient) on the position of a stellar object.

Comparison of stereoscopic technologies in various configurations

  • DOI: 10.1117/12.929237
  • Link: https://doi.org/10.1117/12.929237
  • Department: Department of Radioelectronics
  • Annotation:
    The aim of this paper is twofold. In the first part of the paper we present results of subjective quality assessment based comparison of stereoscopic technologies in various configurations. Subjective assessment has been done on a limited set of observers while using a database of stereoscopic test videos of various source types. There is also comparison of results obtained with the same stereoscopic content from the two cooperating test laboratories. The results can be used to address different aspects of viewing experience, especially comparing passive and active stereoscopic display technologies. The second part of the paper is focused on preliminary experimental results analyzing the vergence-accommodation conflict present in current stereoscopic systems. Simultaneous measurement of the vergence and accommodation has been done with observers viewing a real scene and its stereoscopic reproduction.

Comparison of the astronomical and multimedia image quality criteria

  • DOI: 10.1117/12.923586
  • Link: https://doi.org/10.1117/12.923586
  • Department: Department of Radioelectronics
  • Annotation:
    This paper deals with the criteria definition of image quality in astronomy and their comparison with common multimedia approaches. Astronomical images have typical specific properties - high grayscale bit depth, size, high noise occurrence, sensitivity to point spread function deformation and special processing algorithms. They belong to the class of scientific images as well as medical or similar. Their processing and compression is quite different from the classical approach of multimedia image processing. The new compression algorithm based on JPEG2000 is selected as a distortion source in this paper. Selected image quality criteria (multimedia and optimized for astronomical images) are tested on the set of images from the DEIMOS image database with miscellaneous level of the thermally generated CCD noise. The deformation of the point spread function (PSF) is also measured for chosen compression approach.

Estimation of non-Gaussian noise parameters in the wavelet domain using the moment-generating function

  • DOI: 10.1117/1.JEI.21.3.039802
  • Link: https://doi.org/10.1117/1.JEI.21.3.039802
  • Department: Department of Radioelectronics
  • Annotation:
    We discuss methods for modeling and removal of noise in astronomical images. For its favorable properties, we exploit the undecimated wavelet representation and apply noise suppression in this domain. Usually, the noise analysis of the studied imaging system is carried out in the spatial domain. However, noise in astronomical data is non-Gaussian, and thus the noise model parameters need to be estimated directly in the wavelet domain. We derive equations for estimating the sample moments for non-Gaussian noise in the wavelet domain. We consider that the sample moments in the spatial domain are known from the noise analysis and that the model parameters are estimated by using the method of moments.

Estimation of non-Gaussian noise parameters in the wavelet domain using the moment-generating function

  • DOI: 10.1117/1.JEI.21.2.023025
  • Link: https://doi.org/10.1117/1.JEI.21.2.023025
  • Department: Department of Radioelectronics
  • Annotation:
    We discuss methods for modeling and removal of noise in astronomical images. For its favorable properties, we exploit the undecimated wavelet representation and apply noise suppression in this domain. Usually, the noise analysis of the studied imaging system is carried out in the spatial domain. However, noise in astronomical data is non-Gaussian, and thus the noise model parameters need to be estimated directly in the wavelet domain. We derive equations for estimating the sample moments for non-Gaussian noise in the wavelet domain. We consider that the sample moments in the spatial domain are known from the noise analysis and that the model parameters are estimated by using the method of moments.

Utilization of Image Intensifiers in Astronomy

  • Department: Department of Radioelectronics
  • Annotation:
    In this paper we present the properties of image intensifiers, used together with fast TV cameras for astronomical purposes within the MAIA project(Meteor Automatic Imager and Analyser, primarily focused on observing meteoric events with high time resolution). The main objective of our paper is to evaluate the suitability of these devices for astronomical purposes in terms of noise, temporal and spectral analysis.

Advanced Processing of Images Obtained from Wide-field Astronomical Optical Systems

  • Department: Department of Radioelectronics
  • Annotation:
    The principal aim of this paper is to present a general view of the special optical systems used for acquiring astronomical image data, commonly referred to as WFC or UWFC (Ultra Wide Field Camera), and of their transfer characteristics. UWFC image data analysis is very difficult in general, not only because the systems have so-called space variant (SV) properties. Images obtained from UWFC systems are usually incorrectly presented due to a wide range of optical aberrations and distortions. The influence of the optical aberrations increases towards the margins of the field of view. These aberrations distort the point spread function of the optical system and rapidly cut the accuracy of the measurements. This paper deals with simulation and modelling of the UWFC optical systems used in astronomy and their transfer characteristics.

Analysis and suppression of noise in astronomical video

  • DOI: 10.1109/RADIOELEK.2011.5936386
  • Link: https://doi.org/10.1109/RADIOELEK.2011.5936386
  • Department: Department of Radioelectronics
  • Annotation:
    This paper is devoted to noise suppression in systems for double station observation of meteors, nowadays known as MAIA (Meteor Automatic Imager and Analyzer). The noise analysis based on acquisition of testing video sequences at different lighting conditions and their statistical evaluation were described in our previous paper. The measurement showed that the type of noise generated by the system is signal-independent in a certain illumination range. The noise and image models in the wavelet domain are based on the Generalized Laplacian Model (GLM) and it is the most convenient to estimate the model parameters using the moment method. Furthermore, the noise component may be modeled by the GLM also in the space domain. Overall, we verified that the GLM allows for modeling various types of probability density functions. In the final section of this paper, the performance of the proposed advanced de-noising algorithm is verified on the real data, which were acquired in the Astronomical Institute.

Application of Wavelet Transform for Image Denoising of Spatially and Time Variable Astronomical Imaging Systems

  • Authors: Blažek, M., Anisimova, E., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Acta Polytechnica. 2011, 51(2), 11-15. ISSN 1210-2709.
  • Year: 2011
  • Department: Department of Radioelectronics
  • Annotation:
    We report on our efforts to formulate algorithms for image signal processing with the spatially and time variant Point-Spread Function (PSF) and inhomogeneous noise of real imaging systems. In this article we focus on application of the wavelet transform for denoising of the astronomical images with complicated conditions. They influence above all accuracy of the measurements and the new source detection ability. Our aim is to test the usefulness of Wavelet transform (as the standard image processing technique) for astronomical purposes.

Astronomical Image Compression Techniques Based on ACC and KLT Coder

  • Department: Department of Radioelectronics
  • Annotation:
    This paper deals with a compression of image data in applications in astronomy. Astronomical images have typical specific properties - high grayscale bit depth, size, noise occurrence and special processing algorithms. They belong to the class of scientific images. Their processing and compression is quite different from the classical approach of multimedia image processing. The database of images from BOOTES (Burst Observer and Optical Transient Exploring System) has been chosen as a source of the testing signal. A comparison of two irrelevancy reduction methods is presented from a scientific (astrometric and photometric) point of view. The first method is based on a statistical approach, using the Karhunen-Loeve transform (KLT) with uniform quantization in the spectral domain. The second technique is derived from wavelet decomposition with adaptive selection of used prediction coefficients. Finally, the comparison of three redundancy reduction methods is discussed.

Automatic Video System for Continues Monitoring of the Meteor Activity

  • DOI: 10.1007/s11038-011-9380-9
  • Link: https://doi.org/10.1007/s11038-011-9380-9
  • Department: Department of Radioelectronics
  • Annotation:
    In this paper we present current progress in development of new observational instruments for the double station video experiment. The Meteor Automatic Imager and Analyser (MAIA) system is based on digital monochrome camera JAI CM-040 and well proved image intensifier XX1332. Both the observations as well as the data processing will be fully automatic. We are expecting the recorded data of better quality and both spatial and time resolution in comparison with currently used analogue system. The main goal of the MAIA project is to monitor activity of the meteor showers and sporadic meteor each night for the period of at least 3 years. First version of the system was already assembled and has been intensively tested in the optical laboratory. Optical properties were measured and the result confirmed our expectations according to image quality and resolution. First night sky observation was already carried out.

CCD noise influence on JPEG2000 compression of astronomical images

  • Authors: prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Photonics, Devices, and Systems V. Bellingham: SPIE, 2011. pp. 1-6. Proceedings of SPIE. ISSN 0277-786X. ISBN 978-0-8194-8953-1.
  • Year: 2011
  • DOI: 10.1117/12.912322
  • Link: https://doi.org/10.1117/12.912322
  • Department: Department of Radioelectronics
  • Annotation:
    Compression of astronomical images is still current task. In most applications, lossless approaches are used that do no damage to the compressed data. These algorithms, however, have lower compression ratios and are not as effective. It is therefore important to deal with more efficient lossy compression techniques. For them it is necessary to define quality criteria and level of acceptable distortion of image data. The usual multimedia approach is not possible to use for the scientific image data. They are optimized for human vision. This work deals with the influence of noise generated in the CCD structure to the defined quality criteria. It will also be shown the impact of the lossy standard JPEG2000 on quality of image data in astronomy.

DEIMOS - an Open Source Image Database

  • Department: Department of Radioelectronics
  • Annotation:
    The DEIMOS (DatabasE of Images: Open Source) is created as an open-source database of images and videos for testing, verification and comparing of various image and/or video processing techniques such as enhancing, compression and reconstruction. The main advantage of DEIMOS is its orientation to various application fields - multimedia, television, security, assistive technology, biomedicine, astronomy etc. The DEIMOS is/will be created gradually step-by-step based upon the contributions of team members. The paper is describing basic parameters of DEIMOS database including application examples.

Enhancement of the accuracy of the astronomical measurements carried on the wide-field astronomical image data

  • DOI: 10.1117/12.894117
  • Link: https://doi.org/10.1117/12.894117
  • Department: Department of Radioelectronics
  • Annotation:
    The properties of wide-field astronomical systems along with specific visual data in astronomical images contribute to complicated evaluation of acquired image data. The main goal of this paper is to present the advanced processing of the images obtained from wide-field astronomical systems and to introduce the way how to enhance the accuracy of astronomical measurements on these systems. The paper also deals with the modelling of the space variant high order optical aberrations which increase towards margins of the field of view and which distort the point spread function of optical system and negatively affect the image quality.

Influence of the Lossy Compression JPEG2000 standard on the Deformation of PSF

  • Department: Department of Radioelectronics
  • Annotation:
    This paper deals with the influence of lossy compression algorithms on the deformation of the point spread function (PSF) of imaging systems in astronomy. Lossy compression algorithms reduce irrelevant information in image functions, and their application distorts the image function. Astronomical images have typical specific properties - high grayscale bit depth, size, noise occurrence and special processing algorithms. They belong to the class of scientific images as well as medical or similar. Their processing and compression is quite different from the classical approach of multimedia image processing. The influence of the JPEG2000 coder on the deformation of PSF is presented in this paper.

Low Cost Optical All Sky Monitoring Camera: Further Developments and Tests

  • DOI: 10.1063/1.3621808
  • Link: https://doi.org/10.1063/1.3621808
  • Department: Department of Radioelectronics
  • Annotation:
    We report on the further development and tests of an low-cost optical all-sky monitor recently tested at the Karlovy Vary Observatory. The recent instrumentation is simple based on a Sigma 8 mm f3.5 EX DG fish-eye lens and CANON 1000D digital CMOS camera. It is a low-cost device suitable for easy replication and still able to detect brighter optical transients simultaneously to GRB triggers. Such OTs have been observed for some of the GRBs such as GRB990123, GRB060117, or recently GRB0803 indicating that some fraction of GRBs can generate optical transient emission accessible by simple small aperture instrumentation as described here. These efforts are accompanied by development of dedicated programmes to access and to evaluate all-sky images, these efforts will be also briefly described.

MAIA: Technical Development of a Novel System for Video Observations of Meteors

  • Department: Department of Radioelectronics
  • Annotation:
    A system for double station observation of meteors now known as MAIA (Meteor Automatic Imager and Analyzer) is introduced in this paper. The system is based on two stations with gigabite ethernet cameras, sensitive image intensifiers and automatic processing of the recorded image data. This paper presents the measured electrooptical characteristics of the components and the overall performance of the new digital system in comparison with the current analog solution.

Meteor automatic imager and analyzer: current status and preprocessing of image data

  • DOI: 10.1117/12.893700
  • Link: https://doi.org/10.1117/12.893700
  • Department: Department of Radioelectronics
  • Annotation:
    In this paper we present current progress in development of new observational instruments for the double station video experiment called MAIA (Meteor Automatic Imager and Analyzer). The main goal of the MAIA project is to monitor activity of the meteor showers and sporadic meteors. This paper presents detailed analysis of imaging parameters based on acquisition of testing video sequences at different light conditions. Among the most important results belong the analysis of opto-electronic conversion function and noise characteristics. Based on these results, requirements for image preprocessing algorithms are proposed.

Noise Analysis of MAIA System and Possible Noise Suppression

  • Department: Department of Radioelectronics
  • Annotation:
    This paper is devoted to the noise analysis and noise suppression in a system for double station observation of the meteors now known as MAIA (Meteor Automatic Imager and Analyzer). The noise analysis is based on acquisition of testing video sequences in different light conditions and their further statistical evaluation. The main goal is to find a suitable noise model and subsequently determine if the noise is signal dependent or not. Noise and image model in the wavelet domain should be based on Gaussian mixture model (GMM) or Generalized Laplacian Model (GLM) and the model parameters should be estimated by moment method. Furthermore, noise should be modeled by GMM or GLM also in the space domain. GMM and GLM allow to model various types of probability density functions. Finally the advanced denoising algorithm using Bayesian estimator is applied and its performance is verified.

Open source database of images DEIMOS: high dynamic range and stereoscopic content

  • DOI: 10.1117/12.893786
  • Link: https://doi.org/10.1117/12.893786
  • Department: Department of Radioelectronics
  • Annotation:
    In this paper we present current progress in the project DEIMOS (Database of Images: Open Source). The DEIMOS database is an open-source database of images and videos for testing, verification and comparison of various image and/or video processing techniques. This paper presents additionally measured camera data available with high dynamic range image content and description of stereoscopic content available in the database. The database of stereoscopic images with various parameters in acquisition and image processing is intended for testing and optimization of metrics for objective image quality assessment. An example experiment of perceived image quality assessment depending on particular testing condition in stereoscopic image acquisition is presented. The database will be gradually annotated with mean opinion scores of perceived image quality from human observes for each testing condition.

Stellar Object Detection Using the Wavelet Transform

  • Authors: Anisimova, E., prof. Mgr. Petr Páta, Ph.D., Blažek, M.
  • Publication: Acta Polytechnica. 2011, 51(6), 9-12. ISSN 1210-2709.
  • Year: 2011
  • Department: Department of Radioelectronics
  • Annotation:
    Several algorithms are used nowadays for detecting stellar objects in astronomical images, for example in the DAOPHOT program package and in SExtractor (Software for source extraction). Our team has become acquainted with the wavelet transform and its good localization properties. After studying the manual for DAOPHOT and SExtractor, and becoming familiar with the a trous algorithm used for calculating the wavelet transform, we set ourselves the task to implement an ` algorithm for star detection on the basis of the wavelet transform. We focused on detecting stellar objects in complex fields, such as globular clusters and galaxies. This paper describes a stellar object detection algorithm with the help of the wavelet transform, and presents our results.

Wavelet Transform for Processing of Video from MAIA System

  • DOI: 10.1117/12.912324
  • Link: https://doi.org/10.1117/12.912324
  • Department: Department of Radioelectronics
  • Annotation:
    This article will present the use of wavelet transforms for image processing system of MAIA (Meteor Automatic Imager and Analyser). The main objective of these algorithms is the ob- ject detection with a high proportion of background noise and complicated imaging function. This noise is generated high brightness of the sky, an image intensifier and CCD sensor used. Analyzed images contain a large number of objects, which have dimensions of only a few pix- els. In such cases, it is very difficult to use conventional methods of analysis images that are failing. Application of wavelet transform allows the use of specific features of image function and effectively detect objects.

Detection of GRBs and OTs by All-Sky Optical and SID Monitors

  • DOI: 10.1155/2010/428943
  • Link: https://doi.org/10.1155/2010/428943
  • Department: Department of Radioelectronics
  • Annotation:
    We report on two alternative simple methods to detect counterparts of cosmic gamma-ray bursts (GRBs) and optical transients (OTs). We report on the development and tests of an alternative optical all-sky monitor recently tested at the Karlovy Vary Observatory. The monitor is based on a Peleng 8 mm fish-eye lens (1 : 3,5-1 : 16) and CANON EOS 350D digital CCD camera. This type of monitor represents a low-cost device suitable for easy replication and still able to detect brighter optical transients simultaneously to GRB triggers. Such OTs have been observed for some of the GRBs such as GRB990123, GRB060117, or recently GRB080319 indicating that some fraction of GRBs can generate optical transient emission accessible by simple small aperture instrumentation as described here.

Double-Station Automatic Video Observation of the Meteors

  • DOI: 10.1155/2010/943145
  • Link: https://doi.org/10.1155/2010/943145
  • Department: Department of Radioelectronics
  • Annotation:
    The double station observation of the meteors by means of sensitive image intensifier technique started at the Ondrejov Observatory 10 years ago. The sensitivity of such instrumentation allows detection of the meteors down to masses of fractions of gram. Moreover, video technique provides us with a time resolution of the meteor events. On the other side, the precision of the video data is lower in comparison with the photographic data. We are introducing technological progress on the project-replacing of the S-VHS camcorders with gigabite, ethernet cameras and making the whole process of video observation automatic.

Meteor automatic imager and analyzer: analysis of noise characteristics and possible noise suppression

  • DOI: 10.1117/12.859685
  • Link: https://doi.org/10.1117/12.859685
  • Department: Department of Radioelectronics
  • Annotation:
    This paper is devoted to the noise analysis and noise suppression in a system for double station observation of the meteors now known as MAIA (Meteor Automatic Imager and Analyzer). The noise analysis is based on acquisition of testing video sequences at different light conditions and their further analysis. The main goal is to find a suitable noise model and subsequently determine if the noise is signal dependent or not. Noise and image model in the wavelet domain should be based on Gaussian mixture model (GMM) or Generalized Laplacian Model (GLM) and the model parameters should be estimated by moment method. GMM and GLM allow to model various types of probability density functions. Finally the advanced de-noising algorithm using Bayesian estimator will be applied.

Meteor automatic imager and analyzer: system design and its parameters

  • DOI: 10.1117/12.859935
  • Link: https://doi.org/10.1117/12.859935
  • Department: Department of Radioelectronics
  • Annotation:
    A system for double station observation of the meteors now known as MAIA (Meteor Automatic Imager and Analyzer) is introduced in the paper. This system is an evolution of current analog solution. The system is based on the two stations with the gigabite ethernet cameras, sensitive image intensifiers and automatic processing of the recorded image data. The aim of such design is to capture and analyze images of meteors down to masses of fractions of gram. This paper presents the measured electrooptical characteristics of the particular components and the overall performance of the new digital system in the comparison to the current analog solution. At first the optimal settings of various parameters for each subsystem (primary lens, image intensifier, secondary lens and camera) are determined. Then the set of test images is captured and analyzed. The analysis of the images captured with both artificial and real targets verifies the suitability of the selected system design.

New open source image database for testing and optimization of image processing algorithms

  • DOI: 10.1117/12.854465
  • Link: https://doi.org/10.1117/12.854465
  • Department: Department of Radioelectronics
  • Annotation:
    Development, testing, verification and comparison of various image processing techniques require suitable database of test images. In this paper the DEIMOS, an open-source database, is introduced. This database is aiming various application fields of image processing such as enhancement, compression and reconstruction. At first requirements on different image classes are defined in respect to the specific area of application. The paper also describes basic parameters of the database. There are selected application examples to illustrate extensive database content. The DEIMOS database is created gradually step-by-step based upon the contributions of team members.

Nobel Prize in Physics 2009

  • Department: Department of Radioelectronics
  • Annotation:
    The text deals to Nobel Prize in physic in 2009. W. S. Boyl and G. E. Smith obtained half of Nobel Prize for discovering of the CCD technology. This technology allowed growth of imaging techniques. The basic principles for CCD imaging are described in the paper.

Open source database of images DEIMOS: high dynamic range images

  • DOI: 10.1117/12.859940
  • Link: https://doi.org/10.1117/12.859940
  • Department: Department of Radioelectronics
  • Annotation:
    Efficient development of image processing techniques requires a database of suitable test images for verification of the performance, optimization and other related purposes. In this paper, the DEIMOS, an open-source database, is described including its structure and interface. There is a selected application example on high dynamic range content to illustrate the database features. This HDR image database contains a variety of natural scenes captured with a digital single-lens reflex camera (DSLR) under different conditions. The important capture parameters as well as the important characteristics of the camera are part of the database to ensure that the creation of each image is well documented. The DEIMOS database is created gradually step-by-step based upon the contributions of team members.

Utilization of consumer level digital cameras in astronomy

  • DOI: 10.1117/12.860981
  • Link: https://doi.org/10.1117/12.860981
  • Department: Department of Radioelectronics
  • Annotation:
    This paper presents a study of possible utilization of digital single-lens reflex (DSLR) cameras in astronomy. The DSLRs have a great advantage over the professional equipments in better cost efficiency with comparable usability for selected purposes. The quality of electro-optical system in the DSLR camera determines the area where it can be used with acceptable precision. At first a set of important camera parameters for astronomical utilization is introduced in the paper. Color filter array (CFA) structure, demosaicing algorithm, image sensor spectral properties, noise and transfer characteristics are the parameters that belong among the very important ones and these are further analyzed in the paper. Compression of astronomical images using the KLT approach is also described below. The potential impact of these parameters on position and photometric measurement is presented based on the analysis and measurements with the wide-angle lens.

Advanced processing of astronomical images obtained from optical systems with ultra wide field of view

  • Authors: Řeřábek, M., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: 4th EOS Topical Meeting on Advanced Imaging Techniques. Hannover: European Optical Society Coherence for Europe, 2009. pp. 78-79. ISBN 978-3-00-024189-5.
  • Year: 2009
  • Department: Department of Radioelectronics
  • Annotation:
    The principal aim of this paper is to present a general view of the special optical systems used for acquiring of the astronomical image data, which are commonly called WFC (Wide Field Camera) or UWFC (Ultra Wide Field Camera, and of their transfer characteristics.

Advanced processing of astronomical images obtained from optical systems with ultra wide field of view

  • Authors: Řeřábek, M., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Applications of Digital Image Processing XXXII. Bellingham (stát Washington): SPIE, 2009. p. 1-4. ISSN 0277-786X. ISBN 978-0-8194-7733-0.
  • Year: 2009
  • Department: Department of Radioelectronics
  • Annotation:
    The principal aim of this paper is to present a general view of the special optical systems used for acquiring of the astronomical image data, which are commonly called WFC or UWFC (Ultra Wide Field Camera), and of their transfer characteristics. UWFC image data analysis is very difficult. Images obtained from UWFC systems are distorted by many various optical aberrations. The influence of optical aberrations increases towards margins of the field of view. These aberrations distort the point spread function of the optical system and rapidly cut the accuracy of measurements. UWFC systems frequently have so called spatially variant properties. This paper deals with simulation and modeling of the UWFC optical systems used in astronomy and their transfer characteristics.

Alternative methods for detection of GRBs

  • Department: Department of Radioelectronics
  • Annotation:
    We report on two altenative simple methos to detect counterparts of cosmic gamma-ray bursts (GRBs). We report on the development and tests of an alternative optical all-sky monitor recently tested at the Karlovy Vary Observatory. The monitor is based on a Peleng 8 mm .sh-eye lens (1:3,5-1:16) and CANON EOS 350D digital CCD camera. This type of monitor represents a low-cost device suitable for easy replication and still able to detect brighter optical transients simultaneously to GRB triggers. Such OTs have been observed for some of the GRBs such as GRB990123, GRB060117, or recently GRB0803 indicating that some fraction of GRBs can generate optical transient emission accessible by simple small aperture instrumentation as described here. These efforts are accompanied by development of dedicated programmes to access and to evaluate all-sky images,.. The sekond method is the GRB detection based on thein ionospheric response.

Low-Cost Optical All-Sky Monitor For Detection of Bright OTs of GRBs

  • Authors: prof. RNDr. René Hudec, CSc., Spurny, M., Krizek, P., prof. Mgr. Petr Páta, Ph.D., Řeřábek, M.
  • Publication: Gamma-Ray Burst: Sixth Huntsville Symposium. Austin: American Institute of Physic, 2009. pp. 215-217. AIP Conference Proceedings. ISSN 0094-243X. ISBN 978-0-7354-0670-4.
  • Year: 2009
  • DOI: 10.1063/1.3155881
  • Link: https://doi.org/10.1063/1.3155881
  • Department: Department of Radioelectronics
  • Annotation:
    We report on the development and tests of an alternative optical all-sky monitor recently tested at the Karlovy Vary Observatory. The monitor is based on a Peleng 8 mm fish-eye lens (1:3, 5-1:16) and CANON EOS 350D digital CCD camera. This type of monitor represents a low-cost device suitable for easy replication and still able to detect brighter optical transients simultaneously to GRB triggers. Such OTs have been observed for some of the GRBs such as GRB990123, GRB060117, or recently GRB0803 indicating that some fraction of GRBs can generate optical transient emission accessible by simple small aperture instrumentation as described here. These efforts are accompanied by development of dedicated programmes to access and to evaluate all-sky images, these efforts will be also briefly described. The processing and measuring of image data is complicated and sophisticated deconvolution algorithms are used for image restoration.

Processing and Compression of Astronomical Images from optical All-Sky System

  • Authors: Řeřábek, M., prof. Mgr. Petr Páta, Ph.D., Ing. Karel Fliegel, Ph.D., Koten, P.
  • Publication: 4th EOS Topical Meeting on Advanced Imaging Techniques. Hannover: European Optical Society Coherence for Europe, 2009. pp. 66-67. ISBN 978-3-00-024189-5.
  • Year: 2009
  • Department: Department of Radioelectronics
  • Annotation:
    This paper is aimed at a scientific image data processing and compression. The analyzed data is obtained from all-sky optical systems. An alternative low-cost optical all-sky system for astronomical observing will be briefly described. The study also deals with possibility of Karhunen - Loève Transform (KLT) application for astronomical data compression.

3D KLT compression algorithm for camera security systems

  • Authors: Fritsch, L., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Photonics Prague 2008, The 6th International Conference on Photonics, Devices and Systems. Praha: Agentura Action M, 2008. p. 1-6. ISBN 978-80-86742-25-0.
  • Year: 2008
  • Department: Department of Radioelectronics
  • Annotation:
    This paper deals with an image compression algorithm based on the three- dimensional Karhunen- Loeve transform (3D KLT), whose task is to reduce time redundancy for an image data.

Bayesian approach to estimation of the map of dark current in wavelet domain

  • Department: Department of Radioelectronics
  • Annotation:
    This paper deals with advanced methods for elimination of the thermally generated charge in the astronomical images, which were acquired by Charged Coupled Device (CCD) sensor. There exist a number of light images acquired by telescope, which were not corrected by dark frame. The reason is simple the dark frame doesn't exists, because it was not acquired. This situation may for instance come when sufficient memory space is not available. There will be discussed the correction method based on the modeling of the light and dark image in the wavelet domain. As the model for the dark frame image and for the light image the generalized Laplacian was chosen. The models parameters were estimated using moment method, whereas an extensive measurement on astronomical camera were proposed and done. This measurement simplifies estimation of the dark frame model parameters.

Elimination of Thermally Generated Charge in Charged Coupled Devices Using Bayesian Estimator

  • Department: Department of Radioelectronics
  • Annotation:
    This paper deals with advanced methods for elimination of the thermally generated charge in the astronomical images, which were acquired by Charged Coupled Device (CCD) sensor. There exist a number of light images acquired by telescope, which were not corrected by dark frame. The reason is simple the dark frame doesn't exists, because it was not acquired. This situation may for instance come when sufficient memory space is not available. There will be discussed the correction method based on the modeling of the light and dark image in the wavelet domain. As the model for the dark frame image and for the light image the generalized Laplacian was chosen. The models parameters were estimated using moment method, whereas an extensive measurement on astronomical camera were proposed and done. Finally a set of the astronomical testing images were corrected and then the objective criteria for an image quality evaluation based on the aperture photometry were applied.

KLT Coder for Compression of Security Images

  • Authors: prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Proceedings of 42nd Annual 2008 IEEE International Carnahan Conference on Security Technology. Piscataway: IEEE, 2008. pp. 381-386. ISBN 978-1-4244-1816-9.
  • Year: 2008
  • Department: Department of Radioelectronics
  • Annotation:
    A higher and better precision can been achieved while using more recent security systems and superior detection sensors. It has brought a very rapid increase of data amount as a result. The high resolution (up to ten million pixels) and grey scale images (quantization depth up to 16 bits) accepted in these security applications. A very large volume of image data has been taken during operation of a modern project of automatic monitoring systems. The loss-less compression algorithm has been often required for many applications. Certainly it has not offered achievement of the high compress ratio (up to 2:1 - 5:1 for a special type of images only). The well-known and for the multimedia data optimized lossy methods (JPEG, JPEG2000) have not been suitable. The hopeful results have been achieved with the tests of wavelets or fractal transforms.

Modeling of the widefield space variant security systems

  • Authors: Řeřábek, M., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Proceedings of 42nd Annual 2008 IEEE International Carnahan Conference on Security Technology. Piscataway: IEEE, 2008. pp. 121-125. ISBN 978-1-4244-1816-9.
  • Year: 2008
  • Department: Department of Radioelectronics
  • Annotation:
    The most important methods for security image data processing contain person recognition, suspicious events detection, objects and area of interest analysis and their classification, MSE, SNR and subjective evaluation. Image data processing of UWFC security systems is very difficult in general. Precision of image data post-processing and analyses, which is very important for these systems, decreases because of a lot of different kinds of optical aberrations and distortions. Influence of optical aberrations increases at most at the frontiers of field of view (high angular distance from optical axis of the system). These aberrations distort the PSF of optical system and rapidly cut the accuracy of measurements. The third order optical aberrations models for LSI and LSV systems have been described. These models are based on Seidel and Zernike approximating polynomials. Optical aberrations effect to the transfer function (PSF) of optical imaging systems has been described.

Processing of the Astronomical Image Data obtained from UWFC Optical Systems

  • Authors: Řeřábek, M., prof. Mgr. Petr Páta, Ph.D., Koten, P.
  • Publication: Proceedings of SPIE - 7076 - Image Reconstruction from Incomplete Data V. Washington: SPIE, 2008. pp. 80-90. ISSN 0277-786X. ISBN 978-0-8194-7296-0.
  • Year: 2008
  • Department: Department of Radioelectronics
  • Annotation:
    This paper deals with simulation and modeling of the optical systems used in astronomy and their transfer characteristics. It is especially focused to the WFC (Wide-Field Camera) and UWFC (Ultra Wide-Field Camera) SV (Space Variant) optical systems. The properties of UWFC astronomical systems along with specific visual data in astronomical images contribute to complicated evaluation of acquired image data. There is an experiment for estimate the optical aberration of optical systems described in this paper. The results of different deconvolution algorithms, which are used with partially variant model of UWFC optical system, are demonstrated in this paper.

PSF model of wide-field optical system for restoration of space (in)variant astronomical image data

  • Authors: Řeřábek, M., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Photonics Prague 2008, The 6th International Conference on Photonics, Devices and Systems. Praha: Agentura Action M, 2008. p. 713821-1-713821-7. ISBN 978-80-86742-25-0.
  • Year: 2008
  • Department: Department of Radioelectronics
  • Annotation:
    The third order optical aberrations models for LSI/LSV (Linear Space Invariant/Variant) systems is described in this paper. These models are based on Seidel and Zernike approximating polynomials. Optical aberrations effect to the PSF (Point Sread Function) of optical imaging systems is described as well. Higher quality and precision of image data can be obtained with deconvolution of the acquired images and system point spread function. The PSF can be modelled as a space variant function from the estimation of optical system wavefront aberrations.

The Lossy Compression Technique Based on KLT

  • Authors: prof. Mgr. Petr Páta, Ph.D., Řeřábek, M.
  • Publication: Proceedings of SPIE - 7019 - Advanced Software and Control for Astronomy II. Washington: SPIE, 2008. pp. 701933-1-701933-11. ISSN 0277-786X. ISBN 978-0-8194-7229-8.
  • Year: 2008
  • Department: Department of Radioelectronics
  • Annotation:
    A higher and better precision can been achieved while using more recent observation techniques and superior detection sensors. It has brought a very rapid increase of data amount as a result. The high spatial resolution (up to ten million pixels) and a high bit level grey scale images (quantization depth up to 16 bits) are used in astronomy and other scientific applications. A very large volume of image data has been taken during operation of a modern project of automatic (i.e. robotic) sky observation systems. The coder based on the Karhunen-Loeve transform (KLT) has been chosen for astronomical image compression in this paper. The astrometry and photometry measurements have confirmed a possibility of the coder blocks arrangement with production of an accepted error and a sophisticated data stream.

The space variant PSF for deconvolution of wide-field astronomical images

  • Authors: Řeřábek, M., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Proceedings of SPIE - 7015 - Adaptive Optics Systems. Washington: SPIE, 2008. p. 70152G-1-70152G-12. ISSN 0277-786X. ISBN 978-0-8194-7225-0.
  • Year: 2008
  • Department: Department of Radioelectronics
  • Annotation:
    There are many various applications in astronomy which are using the WFC or UWFC (Ultra Wide-Field Camera) systems. UWFC systems frequently have so called SV (Space Variant) properties. Images obtained in UWFC systems are distorted by high order optical aberrations and objects on ultra wide-field images are very small. If we define the PSF (Point Spread Function) of optical system then we can use some suitable methods for restoration of original image. How to define the point spread function of LSI (Linear Space Invariant) and LSV (Linear Space Variant) systems is one of the most challenging questions of this paper.

High Order Optical Aberrations Influence to Precision of Astronomical Image Data Processing

  • Authors: Řeřábek, M., prof. Mgr. Petr Páta, Ph.D., Koten, P.
  • Publication: Adaptive Optics for Laser Systems and Other Applications. Bellingham: SPIE, 2007. pp. 658409-01-658409-12. ISSN 0277-786X. ISBN 978-0-8194-6712-6.
  • Year: 2007
  • Department: Department of Radioelectronics
  • Annotation:
    There are data evaluation of the astronomical optical systems and description of their transfer characteristics presented in this paper. The real data from the BOOTES (Burst Observer and Optical Transient Exploring Monitor)7 experiment and from double-station video observation of the meteors are analyzed. The BOOTES is a system for monitoring the optical transient of GRB (Gamma Ray Bursts). The main goal of the double-station video observation of the meteors is acquiring of meteors video records and their analysis. Precision of image data post-processing and analyzing, which is very important for these systems, decreases because of a lot of different kinds of optical aberrations and distortions. It proves itself at most on the frontier of the field of view (FOV). This paper includes the description of astronomical data analysis methods and their demos for different values of distortion.

Image data processing of astronomical UWFC systems

  • Authors: Řeřábek, M., prof. Mgr. Petr Páta, Ph.D., Koten, P.
  • Publication: Thidr EOS Topical Meeting on Advanced Imaging Techniques. Hannover: European Optical Society Coherence for Europe, 2007. pp. 70-71. ISBN 978-3-00-020992-5.
  • Year: 2007
  • Department: Department of Radioelectronics
  • Annotation:
    The problems of processing of image data which are obtained from UWFC (Ultra Wide Field Camera) optical systems are presented in this paper. UWFC systems contain a lot of aberrations and therefore they distort the image data. We consider using of the deconvolution method for the correcting of the acquired image data.

Image Quality Evaluation in Security Imaging Systems

  • Department: Department of Radioelectronics
  • Annotation:
    In the paper we discuss selected important facts related to the subjective image quality evaluationand we present some anomalous experimental behavior of image compression techniques.

Quality Measurement of Compressed Astronomical Images by the Coder Based on the Karhunen-Loeve Transform

  • Authors: prof. Mgr. Petr Páta, Ph.D., Řeřábek, M.
  • Publication: Thidr EOS Topical Meeting on Advanced Imaging Techniques. Hannover: European Optical Society Coherence for Europe, 2007. pp. 151-152. ISBN 978-3-00-020992-5.
  • Year: 2007
  • Department: Department of Radioelectronics
  • Annotation:
    The high resolution (up to million pixels) and grey scale images (quantization depth up to 16 bits) are used in astronomy, medicine and other scientific applications. The study deals with possibility of Karhunen - Loeve Transform (KLT) application for astronomical data compression. Achievable compression ratio and efects of the ratio on stellar profile are presented. Real images from BOOTES experiment have been used as testing signals.

Space Variant Point Spread Function Modeling for Astronomical Image Data Processing

  • Department: Department of Radioelectronics
  • Annotation:
    This paper deals with evaluation and processing of astronomical image data, which are obtained by WFC (Wide-Field Camera) or UWFC (Ultra Wide-Field Camera) systems. Precision of astronomical image data post-processing and analyzing is very important. Large amount of different kinds of optical aberrations and distortions is included in these systems. The amplitude of wavefront aberration error increases towards margins of the FOV (Field of View). Relation between amount of high order optical aberrations and astrometry measurement precision is discussed in this paper. There are descriptions of the transfer characteristics of astronomical optical systems presented in this paper. Spatially variant (SV) optical aberrations negatively affect the transfer characteristics of all system and make it spatially variant as well. SV model of optical system is presented in this paper. Partially invariant model of optical systems allows using Fourier methods for deconvolution.

Analysis of Telescope Performance - MTF Approach

  • Department: Department of Radioelectronics
  • Annotation:
    The paper discusses possibilities of small robotic telescopes performance improvement based on knowledge of transfer characteristics (e.g. MTF) of its imaging system

BOOTES-IR: a robotic nIR astronomical observatory devoted to follow-up of transient phenomena

  • DOI: 10.1117/12.671579
  • Link: https://doi.org/10.1117/12.671579
  • Department: Department of Radioelectronics
  • Annotation:
    "BOOTES-IR" is the extension of the BOOTES experiment, which has been operating in Southern Spain since 1998, to the near-infrared (nIR). The goal is to follow up the early stage of the gamma ray burst (GRB) afterglow emission in the nIR, as BOOTES does already at optical wavelengths. The scientific case that drives the BOOTES-IR performance is the study of GRBs with the support of spacecraft like HETE-2, INTEGRAL and SWIFT (and GLAST in the future). Given that the afterglow emission in both, the nIR and the optical, in the instances immediately following a GRB, is extremely bright (reached V = 8.9 in one case), it should be possible to detect this prompt emission at nIR wavelengths too. Combined observations by BOOTES-IR and BOOTES-1 and BOOTES-2 since 2006 can allow for real time identification of trustworthy candidates to have a ultra-high redshift (z > 6). It is expected that, few minutes after a GRB, the nIR magnitudes be H ~ 10-15, hence very high quality spectra can be obtained for objects as far as z = 10 by much larger ground-based telescopes. A significant fraction of observing time will be available for other scientific projects of interest, objects relatively bright and variable, like Solar System objects, brown dwarfs, variable stars, planetary nebulae, compact objects in binary systems and blazars.

Compression of Astronomical Images Based on the Karhunen - Loeve Transform

  • Authors: prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Proceedings of the Eighth IASTED International Conference on Signal and Image Processing. Anaheim: ACTA Press, 2006. pp. 133-138. ISSN 1482-7921. ISBN 978-0-88986-583-9.
  • Year: 2006
  • Department: Department of Radioelectronics
  • Annotation:
    The study deals with possibility of the Karhunen - Loeve Transform (KLT), also known as PCA (Principal Component Analysis), for astronomical data compression. This approach is based on analysis of statistical properties of these kinds of data. Image data are divided into four groups - dark frame (DF), flat field (FF), light image (LI) and deep sky light image (DSLI). Quality measurement of the influence of loss part of the coder has been based on standard signal functions (mean square error - MSE, peak signal to noise ratio PSNR), subjective quality measurement according to ITU standard (International Telecommunication Union) and the efficiency astronomical image processing.

Dark Frame Correction Via Bayesian Estimator in the Wavelet Domain

  • Department: Department of Radioelectronics
  • Annotation:
    It is generally known that every astronomical image which was acquired by CCD sensor, have to be corrected by dark frame. The Dark frame is mapping the dark current of the CCD. May become that we don't have the dark frame image and we cannot directly to correct the astronomical images. This work deals with dark frame correction based on Bayesian estimator in the wavelet domain. The models of the marginal probability density function (PDF) of the wavelet coefficients of astronomical images and dark frame images based on generalized Laplacian is used by this estimator. The parameters of the models, which were mentioned above, were estimated by least square error method on set of the images from our image database.The correction of the astronomical images by dark frame is better than the Bayesian estimator, but further work will deal with more sophisticated Bayesian estimator with more robust statistical description of the images.

Derivate Statistics for Karhunen-Loeve Transform

  • Authors: Hanzlík, P., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Photonics, Devices, and Systems III. Bellingham: SPIE, 2006. pp. 20-1-20-7. Proceedings of SPIE. ISSN 0277-786X. ISBN 0-8194-6236-5.
  • Year: 2006
  • Department: Department of Radioelectronics
  • Annotation:
    Paper presents use of Karhunen-Loeve Transform in video compression and image processing methods.

PDF Model of Multimedia and Scientific Images in the Wavelet Domain

Spatially Adaptive DWT for Image Compression

  • Authors: Schindler, J., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Photonics, Devices, and Systems III. Bellingham: SPIE, 2006. pp. 21-1-21-6. Proceedings of SPIE. ISSN 0277-786X. ISBN 0-8194-6236-5.
  • Year: 2006

Suboptimal Karhunen-Loeve Transform for Compression of Astronomical Images

  • Authors: prof. Mgr. Petr Páta, Ph.D.,
  • Publication: 2006 IEEE International Symposium on Signal Processing and Information Technology. Madison: Omnipress, 2006. pp. 332-337. ISBN 978-0-7803-9753-8.
  • Year: 2006
  • Department: Department of Radioelectronics
  • Annotation:
    This paper deals with a compression of image data in astronomy applications. Astronomical images are typical with their specific properties - high grayscale bit depth, size, noise occurrence and special processing algorithms. They belong to the class of scientific images. Their processing and compression is quite different from the classic approach to the processing of multimedia images. Database of images from BOOTES has been chosen as a source of the testing signal. There is discussed an approach based on analysis of statistical properties of image data in this paper. Eigen-images of the covariance matrix can be used as base vectors of the integral transform known as the Karhunen-Loeve (KLT). This transform minimize deviation from mean square error point of view. The main disadvantage of KLT is its signal dependency and consequently necessity to transfer base vectors with coded data. There is described the suboptimal solution of this problem in this paper.

CCTV Effectiveness Study

GRB 050904: Bootes early R-band detection

  • Department: Department of Radioelectronics
  • Annotation:
    The BOOTES-1B 30 cm robotic telescope in Southern Spain, has followed-up the high-redshift GRB 050904 (Cummings et al. GCN 3910, Haislip et al. 3913, 3914, Reichart et al. 3915, Antonelli et al. GCN 3924) starting 124s after the onset of the burst. The upper limits derived from our R-band filter measurements during the time interval 124s -1100s after the event, together with the values reported by TAROT (Klotz et al. GCN 3917) are consistent with an early decay index of alpha = -1.2 (i.e. in agreement with the value reported at a later epoch in the J-band by Haislip et al. GCN 3914).

Image Quality Evaluation in Applied TV Security Systems

  • Department: Department of Radioelectronics
  • Annotation:
    The paper deals with specific image quality problems in TV security systems when the image compression is used. The image quality optimization criteria are listed and selected examples of real application are demonstrated.

Influence of Lossy Compression Techniques on Processing Precision of Astronomical Images

  • Department: Department of Radioelectronics
  • Annotation:
    Compression of image data from Burst Observer and Optical Transient Exploring System (BOOTES) is discussed. BOOTES project is an international robotic telescope for optical transient of Gamma Ray Bursts (GRB). The statistical distribution of image functions in astronomical images from wide field and deep sky cameras is compared with Gaussian and Laplacean probability density function (pdf). The comparison of two irrelevancy reduction methods is presented from a scientific (astrometry and photometry) point of view. First one is based on a statistical approach to data compression and it is suggested from the Karhunen-Loeve transform (KLT) with uniform quantization in spectral domain. Second technique is derived from wavelet decomposition with adaptive choosing of used mother wavelet.

Qualitative Aspects of Image Compression Methods in Multimedia Systems

Set of Fotonics Experiments and Simulations

  • Authors: Řeřábek, M., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: 13th Annual Conference Proceedings of Technical Computing Prague 2005. Praha: Humusoft, 2005. ISBN 80-7080-577-3.
  • Year: 2005
  • Department: Department of Radioelectronics
  • Annotation:
    V rámci přípravy nového předmětu Obrazová fotonika byla vytvořena kompletní sada úloh. Každá úloha se skládá z části teoretické, experimentální a simulační. Teoretická část seznamuje studenty s problematikou dané úlohy. Experimentální část rozšiřuje úlohu o příslušná měření v laserové laboratoři včetně jejího typického řešení. Poslední část každé úlohy tvoří simulační aplikace vytvořená pomocí nástroje GUI programového vybavení MATLAB.

Simultaneous and optical follow-up GRB observations by BOOTES

  • DOI: 10.1393/ncc/i2005-10137-x
  • Link: https://doi.org/10.1393/ncc/i2005-10137-x
  • Department: Department of Radioelectronics
  • Annotation:
    Since 1998 BOOTES has provided follow-up observations for more than 70 GRBs; the most important results obtained so far are the detection of an OT in the GRB 000313 error box and the non-detection of optical emission simultaneous to the high-energy emission for several GRBs (both long/soft and short/hard events).

Subjective Image Quality Evaluation in Security Imaging Systems

...

3rd Generation Approach to Video Compression for Multimedia

  • Authors: Hanzlík, P., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: MATLAB 2004 - Sborník příspěvků 12. ročníku konference. Praha: VŠCHT, 2004. pp. 175-182. ISBN 80-7080-550-1.
  • Year: 2004

Analyse of Transfer Function of Image Sensors

  • Department: Department of Radioelectronics
  • Annotation:
    Description of a package of algorithms for the simulation and measurement of optical transfer characteristics of imaging sensors.

Basic interpolation methods for Bayer CFA

  • Authors: Hejkal, V., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Digital Technologies 2004. Žilina: Žilinská univerzita, 2004. p. 1-4. ISBN 80-8070-334-5.
  • Year: 2004

Behind the Structure of Video VQ-Coder

BOOTES: A Stereoscopic and Robotic Ground-support Facility for the INTEGRAL Era

  • Authors: Castro-Tirado, A.J., Mateo Sanguino, T.J., de Ugarte Postigo, A., Castro Cerón, J.M., Jelínek, M., Kubánek, P., Hudec, R., doc. Ing. Stanislav Vítek, Ph.D., prof. Mgr. Petr Páta, Ph.D., Ing. Martin Bernas, CSc., Berná, J.A., Soldán, J., Gorosabel, J., Soria, T., de la Morena, B., Reglero, V., Torres, J.
  • Publication: The 5th INTEGRAL Workshop on The INTEGRAL Universe. Noordwijk: European Space Agency, 2004. pp. 637-640. ISSN 0379-6566. ISBN 92-9092-863-8.
  • Year: 2004
  • Department: Department of Radioelectronics
  • Annotation:
    Description of BOOTES - the Burst Observer and Optical Transient Exploring System, aimed towards the detection and study of the optical transients that are generated in conjunction with the elusive Gamma Ray Bursts (GRB).

BOOTES: Technological developments and scientific results by a stereoscopic system with two stations spaced by 240 km

  • DOI: 10.1063/1.1810953
  • Link: https://doi.org/10.1063/1.1810953
  • Department: Department of Radioelectronics
  • Annotation:
    An overview of the technological developments at the Burst Observer and Optical Transient Exploring System (BOOTES) is given. The most important scientific results obtained so far are the detection of an OT in the GRB 000313 error box and the non detection of optical emission simultaneous for GRB 010220, GRB 030226 (long/soft events), GRB 020531 and GRB 021201 (short/hard events). With the recent instrumental and technical developments, BOOTIES multiplies its science capabilities.

Classification Possibilities of Blood Serum Crystallograms in the KLT Domain

  • Authors: Hozman, J., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Biomedical Engineering. Zürich: Acta Press, 2004. pp. 161-164. ISBN 0-88986-379-2.
  • Year: 2004

Lossy Compression of Astronomical Images

  • Authors: Ing. Martin Bernas, CSc., prof. Mgr. Petr Páta, Ph.D., Weinlich, J., Hudec, R., Castro-Tirado, A.
  • Publication: The 5th INTEGRAL Workshop on The INTEGRAL Universe. Noordwijk: European Space Agency, 2004. pp. 829-832. ISSN 0379-6566. ISBN 92-9092-863-8.
  • Year: 2004
  • Department: Department of Radioelectronics
  • Annotation:
    The paper deals with the discussion of the lossless and lossy compression methods of astronomical images.

Optical 2D JTC Processor

  • Department: Department of Radioelectronics
  • Annotation:
    Výpočet 2D korelační funkce je výpočetně velmi náročný. Optická metoda 2D JTC (Joint Transform Correlation) je velmi účinný nástroj mezi ostatními optickými (fotonickými) procesorovými technikami. Původní JTC uspořádání navržené Weaverem a Goodmanem je široce aplikováno a bylo navrženo mnoho modifikací. Praktické použití je však omezeno citlivostí korelační špičky na možná zkreslení a artefakty v obrazu. Příspěvek shrnuje výsledky experimentů pro 2D JTC korelaci. Zkreslení a další jevy jako zvětšení, zmenšení, rotace, zakrytí části obrazu, šum atd. byly studovány včetně vlivu snížené rozlišovací schopnosti a předzpracování obrazu jako součást našich experimentů. Závěrem je prezentován přehled a provedena diskuse o praktických omezením aplikací této 2D korelační techniky. Výzkumné práce byly podpořeny výzkumným záměrem MŠMT č. No. J04/98: 210000022 "Laserové systémy".

PCA Based Compression Technique for the BOOTES Image Data

  • Department: Department of Radioelectronics
  • Annotation:
    The study deals with the possibility of PCA technique (Karhunen-Loeve expansion) application for astronomical data compression. The real images from BOOTES experiment have been used as testing signals.

Robotic observatory tools for wide-field observations

  • Authors: Postigo, A.D., Castro-Tirado, A.J., Sanguino, T. J. M., Palomo, M.T.F, Galiano, J. A. B., Ceron, J. M. C., prof. Mgr. Petr Páta, Ph.D., Soldan, J., Postigo, A-, Hudec, R., Jelinek, M., Vitek, S., Kubanek, P., Carretero, B.A. D., Rierea, J. T., Ing. Martin Bernas, CSc.,
  • Publication: Baltic Astronomy. 2004, 13(4), 696-699. ISSN 1392-0049.
  • Year: 2004
  • Department: Department of Radioelectronics
  • Annotation:
    The Burst Observer and Optical Transient Exploring System (BOOTES) is a project mainly devoted to gamma-ray burst (GRB) research. It has been operating and producing important scientific results since 1998. Here we present two of the technical improvements that will allow BOOTES to keep on the leading edge of GRB investigation: the automatic image analysis software and the wide-field spectrograph.

The System for Autofocusing of Wide-Field Cameras

  • Department: Department of Radioelectronics
  • Annotation:
    Automatic focusing of objectives of robotic telescopes is further important task.A technical solution of autofocusing system is described in this work.

Video Coder based on Vector Quantization

  • Authors: Hanzlík, P., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Proceedings of Workshop 2004. Praha: České vysoké učení technické v Praze, 2004. pp. 288-289. ISBN 80-01-02945-X.
  • Year: 2004

Video Compression for Multimedia Using Karhunen - Loeve Transform and Vector Quantization

  • Authors: Hanzlík, P., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Digital Technologies 2004. Žilina: Žilinská univerzita, 2004. p. 1-4. ISBN 80-8070-334-5.
  • Year: 2004

Effect of BOOTES Image Data Compression using Karhunen-Loeve Decomposition upon Astrometry Measurement Accuracy

Efficient Method for Security Image Data Compression

GRB 030115, simultaneous observations by BOOTES-1

GRB 030226 simultaneous optical observations

Karhunen-Loeve Transform as a Base of BOOTES Image Data Coder

  • Authors: prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Proceedings of the 5th COST 276 Workshop. Praha: České vysoké učení technické v Praze, Fakulta dopravní, 2003. pp. 52-54. ISBN 80-01-02840-2.
  • Year: 2003

Optical Transient Monitor (OTM) for BOOTES Project

Recent Developments in the BOOTES Experiment

  • Authors: de Ugarte Postigo, A., Mateo Sanguino, T.J., Castro Cerón, J.M., prof. Mgr. Petr Páta, Ph.D., Ing. Martin Bernas, CSc., Jelínek, M., prof. RNDr. René Hudec, CSc., McBreen, S., Berná, J.Á., García Dabó, C.E., Gorosabel, J., Más-Hesse, J.M., Soria, T., de la Morena, B.A., Torres Riera, J., Castro-Tirado, A.J.
  • Publication: AIP Conference Proceedings 662. Cambridge: Massachusetts Institute of Technology, 2003. pp. 553-555. ISBN 0-7354-0122-5.
  • Year: 2003

The BOOTES experiment in support of the Gran Telescopio Canarias (GTC) in the study of the high energy universe

  • Authors: Ceron, CJMC, Postigo, AD, Garcia-Dabo, C.E., Sanguino, S TJM, prof. Mgr. Petr Páta, Ph.D., Ing. Martin Bernas, CSc., Jelinek, M., Hudec, R., Berna, JA, Gorosabel, J., Mas-Hesse, JM, Castro-Tirado, AJ
  • Publication: SCIENCE WITH THE GTC 10-M TELESCOPE. 2003. pp. 77-80. REVISTA MEXICANA DE ASTRONOMIA Y ASTROFISICA, SERIE DE CONFERENCIAS. ISSN 1405-2059. ISBN 970-32-0608-5.
  • Year: 2003
  • Department: Department of Radioelectronics
  • Annotation:
    A GTC target of opportunity program (ToO) for gamma ray burst (GRB) afterglows will be a very powerful tool for studying the primitive Universe. Photometry and spectroscopy of GRBs are very suitable for tracing the star formation rate of the Universe at high redshifts (prompt optical and near-infrared observations with the GTC could detect GRBs to z less than or similar to 17; Castro-Tirado et al., this volume, p.. 252; Gorosabel et al., this volume, p. 288). BOOTES (Burst Observer and Optical Transient Exploring System) can very efficiently support a ToO at the GTC through its robotized, extremely fast response capabilities. In this paper, we discuss the ongoing effort to finalize a real time, online, automatic data analysis system for BOOTES. Such a system will be able to provide early reliable, and accurate GRB positions (confirmed by satellite) to trigger a GTC ToO.

The Effect of Image Sensor Configurations on Image Quality

The Scientific Image Data Optical Processing

  • Authors: prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Proceedings of Workshop 2003. Praha: České vysoké učení technické v Praze, 2003. pp. 274-275. ISBN 80-01-02708-2.
  • Year: 2003

Two versions of Optical Transient Monitor Software for BOOTES Experiment

Video VQ-Coder, Implementation in Matlab

  • Authors: Hanzlík, P., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: MATLAB 2003. Praha: VŠCHT, 2003. pp. 173-179. ISBN 80-7080-526-9.
  • Year: 2003

Computer Based Assessment of Health Care Quality

  • Authors: prof. Mgr. Petr Páta, Ph.D., Roubík, K.
  • Publication: Biomedical Engineering and Education. Praha: České vysoké učení technické v Praze, 2002, pp. 135-137. ISBN 80-01-02499-7.
  • Year: 2002

Detection of an optical transient following the 13 March 2000 short/hard gamma-ray burst

Education of Photonic Methods of Information Processing at the Department of Radioelectronics, Faculty of Electrical Engineering

Education of Photonic Metohods of Information Processing

Fundamentals of Image Compression Methods

  • Authors: prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Mikroskopie 2002. Praha: České vysoké učení technické v Praze, 2002. pp. 68-77. ISBN 80-01-02580-2.
  • Year: 2002

GRB 020531, simultaneous optical observations

Highly-Efficient Image Compression Techniques and Subjective Image Quality

  • Department: Department of Radioelectronics
  • Annotation:
    The paper is devoted to the impact of modern image compression methods on subjective image quality. Some initial experiments with JPEG, LuRaWave and KLT were done and the objective measures were compared with subjective image quality evaluated by a group of observers.

Image Compression Methods as an Imaging System

  • Department: Department of Radioelectronics
  • Annotation:
    Obviously we can treat the compression algorithm as any linear imaging system. In a standard imaging approach we describe an imaging system by the Point Spread Function PSF or the Modulation Transfer Function (MTF). For the purposes of simulation, however, the compression method can usually, and conveniently, be treated as a "black box" with a possibility to provide the output images. As an example we have selected some of the compression methods based on DCT, Hadamard transform, KLT and fractals . We have used MTF and PSNR because of their important relevance to evaluation from the point of view of the objective image quality.

KL Decomposition of Multimedia Image Data

  • Authors: prof. Mgr. Petr Páta, Ph.D.,
  • Publication: 8. mezinárodní vedecká konferencia COFAX-TELEKOMUNIKÁCIE 2002 Zborník prednášok. Bratislava: D&D STUDIO, 2002. pp. P391-P392. ISBN 80-967019-5-9.
  • Year: 2002

KLT coder in MATLAB

New Methods of Image Quality Evaluation

  • Department: Department of Radioelectronics
  • Annotation:
    Obviously we can treat the compression algorithm as any imaging system. In a standard imaging approach we describe an imaging system by the same parameters as optical imaging systems. We have used the above mentioned parameters because of their important relevance to evaluation from the point of view of the objective image quality, or the objective quality of the compression algorithm.

Optical JTC Applications in Biomedical Image Processing

Software Aid of Scoring and Audit of Trauma for Automatical Evaluation of Czech Traumacentres Health Care Quality

  • Authors: Roubík, K., prof. Mgr. Petr Páta, Ph.D., Pachl, J.
  • Publication: Inteligentní systémy ve zdravotní péči. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 2002, pp. 3.
  • Year: 2002

Testing of Security Application of Optical JTC

The Scientific Data Optical Processing

  • Authors: prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Proceedings of Workshop 2002. Praha: České vysoké učení technické v Praze, 2002. pp. 258-259. ISBN 80-01-02511-X.
  • Year: 2002

Application of Several Compression Methods on Large Databases of Astronomical Images

Application of the Karhunen-Loeve Decomposition for Astronomical Data Storage

BOOTES-1: a Robotic Telescope 1.998 - 2.000

  • Authors: Castro Cerón, J.M., Castro-Tirado, A., Soldán, J., prof. RNDr. René Hudec, CSc., Ing. Martin Bernas, CSc., prof. Mgr. Petr Páta, Ph.D., Mateo Sanguino, T., de Ugarte Postigo, A., Berná, Á., Nekola, M., Gorosabel, J., de la Morena, B., Más-Hesse, J.M., Giménez, Á., Torres Riera, J.
  • Publication: COSMICS EXPLOSIONS: Gamma-Ray Bursts & Related Phenomena. Jerusalem: The Hebrew University of Jerusalem, 2001.
  • Year: 2001

Categorising of Injury Type and Evaluation of Trauma Centres Healthcare Quality

  • Authors: Roubík, K., prof. Mgr. Petr Páta, Ph.D., Pachl, J.
  • Publication: Telekomunikácie 2001 - Zborník prednášok. Bratislava: ADAPT, 2001, pp. 265-267. ISBN 80-968042-3-5.
  • Year: 2001

Design of Compress Algorithms of Scientific Image Data in MATLAB

  • Authors: prof. Mgr. Petr Páta, Ph.D.,
  • Publication: MATLAB 2001. Praha: Vydavatelství VŠCHT Praha, 2001. pp. 334-338. ISBN 80-7080-446-7.
  • Year: 2001

Digital Signal Processing Application in Radioelectronics

Gamma Ray Burst Follow Up Observations with BOOTES-1 in 1998-2000

GRB 010220, Simultaneous Optical Observations by BOOTES-1

KLE or DCT (JPEG) Based Coder?

  • Authors: prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Poster 2001. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 2001. pp. IC34.
  • Year: 2001

Medical Information System for Injury Type Categorising and Quality of Medical Treatment Evaluation

  • Authors: Roubík, K., prof. Mgr. Petr Páta, Ph.D., Pachl, J.
  • Publication: Proceedings of Workshop 2001. Praha: České vysoké učení technické v Praze, 2001, pp. 308-309. ISBN 80-01-02335-4.
  • Year: 2001

Methods of Biosignal Encoding for Telemetry and Diagnostics

  • Authors: prof. Mgr. Petr Páta, Ph.D., Roubík, K.
  • Publication: Telekomunikácie 2001 - Zborník prednášok. Bratislava: ADAPT, 2001, pp. 262-264. ISBN 80-968042-3-5.
  • Year: 2001

New Properties of Optical Transient Monitor (OTM)

New Version of Optical Transient Monitor for BOOTES Project

Objective and Subjective Image Quality Elevation for Security Technology

Optical Methods of Information Processing

Quantization Error of Karhunen-Loeve Expansion of Scientific Images

Search for Gamma Ray Bursts Quasi Simultaneous Optical Emission with BOOTES-1

Selected Techniques for Optical Information Processing - Educational Approach

Subjective Image Quality in Image Processing Systems

The Evaluation of Image Quality in the Modern Multimedia Compression Standards

The Morphological Method of Objects Classification for Astronomy Applications

  • Authors: Charvát, J., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Poster 2001. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 2001. pp. IC14.
  • Year: 2001

The Optical Transient Monitor - A Sky Monitoring System

The TraumaLog Software for Categorising of Injury Type

  • Authors: prof. Mgr. Petr Páta, Ph.D., Roubík, K., Pachl, J.
  • Publication: Proceedings of Workshop 2001. Praha: České vysoké učení technické v Praze, 2001, pp. 310-311. ISBN 80-01-02335-4.
  • Year: 2001

TraumaLog Software

  • Authors: Pachl, J., Roubík, K., prof. Mgr. Petr Páta, Ph.D., Pažout, J., Fric, M., Bakalář, B.
  • Publication: Anestézie u závažných úrazových stavů. Pardubice: Nemocnice v Pradubicích, 2001, pp. 24-30. ISBN 80-86-41703-4.
  • Year: 2001

Two Years of Gamma-Ray Burst Follow-Up Observations with BOOTES-1

Utilizing of MATLAB for Simulation of Optical Information Processing

A Method for Searching of Gaussian Objects in Highly Noise Image

Application of Digital Signal Processing in Radio Engineering

Application of the Karhunen-Loeve Decomposition for Astronomical Data Storage

Biosignals Processing in MATLAB within the Teaching of BME at FEE CTU

  • Authors: Roubík, K., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Sborník příspěvků 8. ročníku konference MATLAB 2000. Praha: Vysoká škola chemicko-technologická, 2000, pp. 341-343. ISBN 80-7080-401-7.
  • Year: 2000

Coding of Scientific Image Data by KLT in MATLAB

  • Authors: prof. Mgr. Petr Páta, Ph.D., Roubík, K.
  • Publication: Sborník příspěvků 8. ročníku konference MATLAB 2000. Praha: Vysoká škola chemicko-technologická, 2000, pp. 310-317. ISBN 80-7080-401-7.
  • Year: 2000

Data Compression for BOOTES Project

First Results from the Burst Observer and Optical Transient Exploring System Station 1 (BOOTES-1)

  • Authors: Castro-Tirado, A.J., Ing. Martin Bernas, CSc., prof. Mgr. Petr Páta, Ph.D., Soldán, J., Hudec, R., de Ugarte, A., Sanguino, T.M., de la Morena, B., Berna, J.A.
  • Publication: The Fifth Huntsville Gamma Ray Burst Symposium - Program & Abstracts. Woodbury: American Institute of Physics, 2000. pp. 260-264. ISBN 1-56396-947-5.
  • Year: 2000

Gamma-Ray Burst Follow-Up Observations with BOOTES-1 in 1998-2000

GRB 000126, Optical Observations

GRB 000313, Optical Transient in the BATSE Error Box

GRB 000607, Optical Observations

Karhunen-Loeve Expansion of Scientific Images

  • Authors: prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Poster 2000. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 2000. pp. IC18.
  • Year: 2000

Lossless and Lossy Compression of Images from the OMC Experiment of Integral Project

Novel Image Data Compression Method Suitable for Satellite Applications

Optical Observations of GRBs: EN, BART and OMC

  • Authors: Hudec, R., Soldán, J., Nekola, M., Florián, J., Hudcová, V., Ing. Martin Bernas, CSc., prof. Mgr. Petr Páta, Ph.D., Palazzi, E., Masetti, N.
  • Publication: The Fifth Huntsville Gamma Ray Burst Symposium - Program & Abstracts. Woodbury: American Institute of Physics, 2000. pp. 265-269. ISBN 1-56396-947-5.
  • Year: 2000

Optical Transient Monitor for BOOTES Project

Properties of Karhunen-Loeve Expansion of Astronomical Images in Comparison with Other Integral Transforms

Two Years of Gamma-Ray Burst Follow-Up Observations with BOOTES-1

BART, BOOTES and OMC: Monitoring of AGNs-blazars

  • Authors: Hudec, R., Soldán, J., Hudcová, V., Ing. Martin Bernas, CSc., prof. Mgr. Petr Páta, Ph.D., Hroch, F., Castro-Tirado, A.J., Mas-Hesse, J.M., Gimenez, A.
  • Publication: Blazar Monitoring towards the Third Millennium, Proceedings of the OJ-94 Annual Meeting 1999. Torino: Osservatorio Astronomico di Torino, 1999. pp. 131-133.
  • Year: 1999

The Burst Observer and Optical Transient Exploring System (BOOTES)

Approaches to Losseles and Loosy Image Compressions Employed in the OMC Experiment Placed Onboard the INTEGRAL OMC

Determination of Transform Matrix Parameters Using Pseudocorrelation Method of Significant Points

First Results of OTM System's Tests

  • Authors: prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Poster 1998. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 1998. pp. 25-26.
  • Year: 1998

Optical Transient Monitor

Status of the BOOTES Experiment

  • Authors: Tirado, A., Hudec, R., Ing. Martin Bernas, CSc., Soldan, J., Gorosabel, J., prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Gamma Ray Bursts, AIP Conference Proceedings. Woodbury: American Institute of Physics, 1998. pp. 874-878. ISBN 1-56396-766-9.
  • Year: 1998

Formulation of Basic Criterions for Real-Time Recognition of Some Objects in Astronomical Images

  • Authors: prof. Mgr. Petr Páta, Ph.D.,
  • Publication: Poster 1997. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 1997. pp. 144.
  • Year: 1997

Methods for Identification of Stars on Astronomical Images

Application of Signal Processors in Detection and Evaluation of Gamma Ray Bursts

Application of Signal processors in Detection and Evaluction of Gamma Ray Bursts

  • Authors: Abraham, M., prof. Mgr. Petr Páta, Ph.D., Zajíček, K.
  • Publication: Poster 1996. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 1996, pp. 26.
  • Year: 1996

Responsible person Ing. Mgr. Radovan Suk