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doc. Ing. Stanislav Vítek, Ph.D.

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Classification of silicate and organic fragments of construction and demolition waste using multisensor techniques

  • Authors: Zbíral, T., Trejbal, J., Ing. Matěj Hužvár, doc. Ing. Stanislav Vítek, Ph.D., Nežerka, V., Valentin, J.
  • Publication: Recycling 2024 - Cirkulární ekonomika ve stavebnictví, recyklace a využívání druhotných stavebních materiálů. Brno Technical University, 2024. p. 106-113. ISBN 978-80-214-6232-8.
  • Year: 2024
  • Department: Department of Radioelectronics
  • Annotation:
    Efficiently sorting individual materials from heterogeneous construction debris poses a persistent challenge in realizing the vision of a circular economy. This paper introduces a technology employing RGB cameras and mass sensors operating in 3D, for rapid and accurate classification of materials. Data is processed through specialized software leveraging extraction techniques, machine learning, and computer vision algorithms. Our technology achieves material determination accuracy ranging from 90% to 96%.

A Directional Particle Filter-Based Multi-Floor Indoor Positioning System

  • Authors: Huang, S., Huang, H., Chong, H.Y., Jiang, J., doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: IEEE Access. 2022, 10 116317-116325. ISSN 2169-3536.
  • Year: 2022
  • DOI: 10.1109/ACCESS.2022.3218462
  • Link: https://doi.org/10.1109/ACCESS.2022.3218462
  • Department: Department of Radioelectronics
  • Annotation:
    In recent years, extensive research and applications have demonstrated that a more accurate and stable indoor positioning system (IPS) can be realized through the complementarity of different technologies. However, improving the accuracy of a single positioning technology would significantly impact the subsequent fusion. In this paper, we proposed a smartphone positioning system based on pedestrian dead reckoning (PDR) fusing with a floor estimation module (FEM) and a directional particle filter (PF) extracted by the idea of a regular PF to improve positioning accuracy. Generally, particles are generated by circle-shaped distribution by a regular PF, leading to producing some useless particles that waste computing resources. To tackle this issue, our proposed directional PF uses the particle more effectively by adjusting the distribution shape of particles with an estimated moving direction. Comprehensive experiments are conducted to verify the positioning accuracy and robustness of the proposed method. The experimental data show that the positioning error of our proposed method is only 1.53 m in a multi-floor path with a total length of 306 m.

A SIMO Hybrid Visible-Light Communication System for Optical IoT

  • DOI: 10.1109/JIOT.2021.3098181
  • Link: https://doi.org/10.1109/JIOT.2021.3098181
  • Department: Department of Electromagnetic Field, Department of Radioelectronics
  • Annotation:
    Visible-light communication (VLC) is an emerging technology utilizing light-emitting diodes and photodetectors (PDs) and cameras [i.e., image sensors (ISs)] as the transmitter and receivers (Rx), respectively, for simultaneous data communications, illumination, localization, and sensing in the indoor optical Internet of Things. We propose a single-input–multiple-output (SIMO) hybrid VLC system using PD-based and IS-based Rxs for simultaneous high-speed and low-speed (i.e., Rb−High and Rb−Low ) data transmission. In addition, we propose amplitude overlapping AOL in the modulation format to increase Rb and reduce the attenuation due to the high-pass filter effect of the bias-T. We experimentally evaluate the performance of the proposed scheme considering the interlink impacts. Results show that at AOL of 0–0.2: 1) the measured bit error rate for the PD-based VLC is below the forward error correction limit of 3.8×10−3 for Rb−Low of 2.5 and 5 kb/s at Rb−High of 35 and 60 Mb/s, respectively, and 2) for the IS-based VLC link with the camera gain of 4 dB and Rb−High of up to 70 Mb/s, the reception success rates are >96 and 90% at Rb−Low of 2.5 and 5 kb/s, respectively.

GRB 190919B: Rapid optical rise explained as a flaring activity

  • DOI: 10.1051/0004-6361/202143010
  • Link: https://doi.org/10.1051/0004-6361/202143010
  • Department: Department of Radioelectronics
  • Annotation:
    Following the detection of a long GRB 190919B by INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory), we obtained an optical photometric sequence of its optical counterpart. The light curve of the optical emission exhibits an unusually steep rise similar to 100 s after the initial trigger. This behaviour is not expected from a 'canonical' GRB optical afterglow. As an explanation, we propose a scenario consisting of two superimposed flares: an optical flare originating from the inner engine activity followed by the hydrodynamic peak of an external shock. The inner-engine nature of the first pulse is supported by a marginal detection of flux in hard X-rays. The second pulse eventually concludes in a slow constant decay, which, as we show, follows the closure relations for a slow cooling plasma expanding into the constant interstellar medium and can be seen as an optical afterglow sensu stricto.

Implementing a Compression Technique on the Progressive Contextual Excitation Network for Smart Farming Applications

  • Authors: Prakosa, S.W., Leu, J.-S., Hsieh, H.-Y., Avian, C., Bai, C.-H., doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: Sensors. 2022, 22(24), ISSN 1424-8220.
  • Year: 2022
  • DOI: 10.3390/s22249717
  • Link: https://doi.org/10.3390/s22249717
  • Department: Department of Radioelectronics
  • Annotation:
    The utilization of computer vision in smart farming is becoming a trend in constructing an agricultural automation scheme. Deep learning (DL) is famous for the accurate approach to addressing the tasks in computer vision, such as object detection and image classification. The superiority of the deep learning model on the smart farming application, called Progressive Contextual Excitation Network (PCENet), has also been studied in our recent study to classify cocoa bean images. However, the assessment of the computational time on the PCENet model shows that the original model is only 0.101 s or 9.9 FPS on the Jetson Nano as the edge platform. Therefore, this research demonstrates the compression technique to accelerate the PCENet model using pruning filters. From our experiment, we can accelerate the current model and achieve 16.7 FPS assessed in the Jetson Nano. Moreover, the accuracy of the compressed model can be maintained at 86.1%, while the original model is 86.8%. In addition, our approach is more accurate than ResNet18 as the state-of-the-art only reaches 82.7%. The assessment using the corn leaf disease dataset indicates that the compressed model can achieve an accuracy of 97.5%, while the accuracy of the original PCENet is 97.7%.

400 m rolling-shutter-based optical camera communications link

  • DOI: 10.1364/OL.385423
  • Link: https://doi.org/10.1364/OL.385423
  • Department: Department of Electromagnetic Field, Department of Radioelectronics
  • Annotation:
    In this Letter, we develop a novel technique, to the best of our knowledge, to increase the link span (𝐿𝑠) of a rolling shutter (RS)-based optical camera communications (OCC) system by reducing the spatial bandwidth of the camera in the out-of-focus regions. We demonstrate a 400 m line-of-sight RS-based OCC link, which is to date the longest 𝐿𝑠 reported in these systems, and develop a detection method to extract the information out of the video frames, successfully. The proposed system relaxes the condition of a large surface area for the transmitter light source. Consequently, we show that at 400 m 𝐿𝑠 and exposure times of 100–80 µs, a data rate of 450 bps is achieved successfully.

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).

Optical Camera Communications for IoT–Rolling-Shutter Based MIMO Scheme with Grouped LED Array Transmitter

  • DOI: 10.3390/s20123361
  • Link: https://doi.org/10.3390/s20123361
  • Department: Department of Electromagnetic Field, Department of Radioelectronics
  • Annotation:
    In optical camera communications (OCC), the provision of both flicker-free illumination and high data rates are challenging issues, which can be addressed by utilizing the rolling-shutter (RS) property of the image sensors as the receiver (Rx). In this paper, we propose an RS-based multiple-input multiple-output OCC scheme for the Internet of things (IoT) application. A simplified design of multi-channel transmitter (Tx) using a 7.2 × 7.2 cm2 small 8 × 8 distributed light emitting diode (LED) array, based on grouping of LEDs, is proposed for flicker-free transmission. We carry out an experimental investigation of the indoor OCC system by employing a Raspberry Pi camera as the Rx, with RS capturing mode. Despite the small area of the display, flicker-free communication links within the range of 20–100 cm are established with data throughput of 960 to 120 bps sufficient for IoT. A method to extend link spans up to 1.8 m and the data throughput to 13.44 kbps using different configurations of multi-channel Tx is provided. The peak signal-to-noise ratio of ~14 and 16 dB and the rate of successfully received bits of 99.4 and 81% are measured for the shutter speeds of 200 and 800 µs for a link span of 1 m, respectively.

The First Study of MIMO Scheme Within Rolling-shutter Based Optical Camera Communications

  • DOI: 10.1109/CSNDSP49049.2020.9249566
  • Link: https://doi.org/10.1109/CSNDSP49049.2020.9249566
  • Department: Department of Electromagnetic Field, Department of Radioelectronics
  • Annotation:
    In this paper, we propose the first study of MIMO (multiple-input multiple-output) scheme using a simplified design of MIMO transmitter (Tx) based on grouping of light-emitting diodes (LED) within an array for flicker-free transmission in optical camera based communications (OCC) link. We carried out an initial experimental investigation of indoor static downlink OCC using a Raspberry Pi camera as the receiver with rolling-shutter capturing mode and a 7.2 cm × 7.2 cm small 64-neopixel LED array as the Tx. The initial study suggests that, despite the small area of the display, communication links from 20 up to 60 cm can be established.

Fast meteor tracking in noisy video sequences

  • DOI: 10.1002/asna.201913670
  • Link: https://doi.org/10.1002/asna.201913670
  • Department: Department of Radioelectronics
  • Annotation:
    Meteor recording, detection, and analysis is one of the traditional topics of astronomy. This paper deals with fast-tracking of faint meteors and meteor showers in video sequences with high frame rates. Since meteors are fast optical events, the utilization of cameras with high frame rates and short exposure times is the standard technique of meteor tracks capture. Low efficiency of such camera systems is typically compensated with image intensifiers, mostly based on the microchannel plate (MCP). In this work, we use image data captured with the meteor automatic imager and analyzer, double-station system dedicated for observing faint meteor showers. The system works with minimal human interaction, and it is necessary to automatically process (i.e., identify all meteor candidates) all captured data as fast as possible. Results show possible speed-up of the image processing method when fluctuations of MCP are reduced.

Optical camera communication system for Internet of Things based on organic light emitting diodes

  • DOI: 10.1049/el.2018.8037
  • Link: https://doi.org/10.1049/el.2018.8037
  • Department: Department of Electromagnetic Field, Department of Radioelectronics
  • Annotation:
    The inclusion of organic light emitting diodes (OLEDs) in high-end devices, such as TVs and smart-phones, along with the insertion of cameras embedded in daily use devices, provides the opportunity to establish optical camera communication (OCC) systems based on OLED emitters for Internet of Things (IoT). This Letter presents an experimental demonstration of this OLED-based OCC system for IoT. The results suggest that despite the low emitted power of OLED devices, long range links can be established based on OCC. One outdoor and two indoor scenarios are tested, validating BER below 10−6 for short range and give just 3.56×10−3 for long range links.

A distributed wireless camera system for the management of parking spaces

  • DOI: 10.3390/s18010069
  • Link: https://doi.org/10.3390/s18010069
  • Department: Department of Radioelectronics
  • Annotation:
    The importance of detection of parking space availability is still growing, particularly in major cities. This paper deals with the design of a distributed wireless camera system for the management of parking spaces, which can determine occupancy of the parking space based on the information from multiple cameras. The proposed system uses small camera modules based on Raspberry Pi Zero and computationally efficient algorithm for the occupancy detection based on the histogram of oriented gradients (HOG) feature descriptor and support vector machine (SVM) classifier. We have included information about the orientation of the vehicle as a supporting feature, which has enabled us to achieve better accuracy. The described solution can deliver occupancy information at the rate of 10 parking spaces per second with more than 90% accuracy in a wide range of conditions. Reliability of the implemented algorithm is evaluated with three different test sets which altogether contain over 700,000 samples of parking spaces.

Background estimation in difficult light conditions

  • Authors: Nasyrova, M., doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: 2018 28th International Conference Radioelektronika. IEEE (Institute of Electrical and Electronics Engineers), 2018. p. 1-4. ISBN 978-1-5386-2485-2.
  • Year: 2018
  • DOI: 10.1109/RADIOELEK.2018.8376367
  • Link: https://doi.org/10.1109/RADIOELEK.2018.8376367
  • Department: Department of Radioelectronics
  • Annotation:
    This paper presents an approach to background estimation in video-sequences from surveillance cameras placed in places with unexpected and massive changes in light conditions such as tunnels or railroad tracks. In those locations, it is necessary to ensure the safety of persons who may be present in the observed area. In the case of automated video monitoring, safety can be ensured only if the algorithm used to detect and classify objects in the camera field of view has high efficiency. Since the most of the detection algorithms are based on the difference of the consecutive frames, complicated surroundings like moving wagons or reflections produce a high number of false alerts, so the performance of the algorithms is weak in term of the accuracy. In this paper, we propose a method to eliminate false detection caused by a change of illumination.

Real-Time Detection of Sporadic Meteors in the Intensified TV Imaging Systems

  • DOI: 10.3390/s18010077
  • Link: https://doi.org/10.3390/s18010077
  • Department: Department of Radioelectronics
  • Annotation:
    The automatic observation of the night sky through wide-angle video systems with the aim of detecting meteor and fireballs is currently among routine astronomical observations. The observation is usually done in multi-station or network mode, so it is possible to estimate the direction and the speed of the body flight. The high velocity of the meteorite flying through the atmosphere determines the important features of the camera systems, namely the high frame rate. Thanks to high frame rates, such imaging systems produce a large amount of data, of which only a small fragment has scientific potential. This paper focuses on methods for the real-time detection of fast moving objects in the video sequences recorded by intensified TV systems with frame rates of about 60 frames per second. The goal of our effort is to remove all unnecessary data during the daytime and make free hard-drive capacity for the next observation. The processing of data from the MAIA (Meteor Automatic Imager and Analyzer) system is demonstrated in the paper.

Analysis of nonline-of-sight visible light communications

  • DOI: 10.1117/1.OE.56.11.116116
  • Link: https://doi.org/10.1117/1.OE.56.11.116116
  • Department: Department of Electromagnetic Field, Department of Radioelectronics
  • Annotation:
    We analyze the channel properties of a nonline-of-sight (NLOS) ceiling-to-device and device-to device visible light communication systems by considering various receivers' orientation and variable fields of view (FOVs). Analyses based on the recursive indoor channel model show that for a particular transmitter configuration, the pure NLOS path can offer higher 3-dB channel bandwidth (up to 14 MHz) compared with the link with LOS and NLOS components. We also show how the receiver rotation (orientation) influences the probability of receiving signals via the NLOS path compared with the LOS and NLOS paths. Moreover, based on the experimental campaign, we demonstrate that shadowing observed at the receiver due to people’s movement results in decreased received power level (up to 1.8 dB), thus resulting in reshaping of the probability density function of received power.

Estimation of Poisson noise in spatial domain

  • DOI: 10.1117/12.2274149
  • Link: https://doi.org/10.1117/12.2274149
  • Department: Department of Radioelectronics
  • Annotation:
    This paper deals with modeling of astronomical images in the spatial domain. We consider astronomical light images contaminated by the dark current which is modeled by Poisson random process. Dark frame image maps the thermally generated charge of the CCD sensor. In this paper, we solve the problem of an addition of two Poisson random variables. At first, the noise analysis of images obtained from the astronomical camera is performed. It allows estimating parameters of the Poisson probability mass functions in every pixel of the acquired dark frame. Then the resulting distributions of the light image can be found. If the distributions of the light image pixels are identified, then the denoising algorithm can be applied. The performance of the Bayesian approach in the spatial domain is compared with the direct approach based on the method of moments and the dark frame subtraction.

Evaluation of co-added astronomical images

  • Authors: Nasyrova, M., doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: Contributions of the Astronomical Observatory Skalnaté Pleso. 2017, 47(2), 208-214. ISSN 1335-1842.
  • Year: 2017
  • Department: Department of Radioelectronics
  • Annotation:
    The co-adding, averaging, or stacking of data are popular techniques to improve scientific outcomes in astronomy, especially in the case of extraction of very faint sources. These methods allow to increase the signal-tonoise ratio and to decrease the point spread function width, which improves the accuracy of segmentation. This paper deals with a brief review of image co-adding algorithms and their evaluation regarding improving the qualitative parameters of the image data.

Influence of camera setting on vehicle-to-vehicle VLC employing undersampled phase shift on-off keying

  • DOI: 10.13164/re.2017.0946
  • Link: https://doi.org/10.13164/re.2017.0946
  • Department: Department of Electromagnetic Field, Department of Radioelectronics
  • Annotation:
    This paper focuses on the performance analysis of a camerabased vehicle-to-vehicle visible light communication system employing undersampled phase shift on-off keying modulation under interference scenario. Two Nissan Qashqai front lights with daylight running light emitting diodes based lamps are used for communications. The bit error rate (BER) performance of the proposed system is experimentally measured for a transmission span up to 24mfocusing mostly on the side interference due to reflections. Based on experimental data we demonstrate reduction of the system performance due to the side reflection and illumination of the detector by other light sources which have to be taken into account during further data processing. We provide with further statistics for particular shutter speed and transmitter power setting and discuss BER improvement especially to meet FEC via the method of the adaptive region of interest.

Light-pollution measurement with the Wide-field all-sky image analyzing monitoring system

  • Authors: doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: Contributions of the Astronomical Observatory Skalnaté Pleso. 2017, 47(2), 215-219. ISSN 1335-1842.
  • Year: 2017
  • Department: Department of Radioelectronics
  • Annotation:
    The purpose of this experiment was to measure light pollution in the capital of Czech Republic, Prague. As a measuring instrument is used calibrated consumer level digital single reflex camera with IR cut filter, therefore, the paper reports results of measuring and monitoring of the light pollution in the wavelength range of 390 - 700 nm, which most affects visual range astronomy. Combining frames of different exposure times made with a digital camera coupled with fish-eye lens allow to create high dynamic range images, contain meaningful values, so such a system can provide absolute values of the sky brightness.

Quality assessment of glass jewelry stones

  • Authors: Nasyrova, M., doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: Proc. SPIE 10603, Photonics, Devices, and Systems VII. Bellingham (stát Washington): SPIE, 2017. p. 106030D-1-106030D-7. Proceedings of SPIE. vol. 10603. ISSN 0277-786X. ISBN 978-1-5106-1702-5.
  • Year: 2017
  • DOI: 10.1117/12.2292541
  • Link: https://doi.org/10.1117/12.2292541
  • Department: Department of Radioelectronics
  • Annotation:
    The increasing demand for the efficiency in the fabrication of jewelry stones pushes producers to look for new and fast methods of the quality control. One possible way, how to reach satisfactory results, is to use the camera-based system and appropriate methods of image post-processing. Since the glass stones are very small, this task is quite challenging. This paper focuses on methods of quality assessment of the glass jewelry stones and proposes semi-automatic method of their classification based on stone feature detection and distance transform. This algorithm includes rough stone classification, which achieves 93.97% hits in our experiment, and classification based on the evaluation of single stone facets with 96.67% hits.

Radiometric calibration of wide-field camera system with an application in astronomy

  • DOI: 10.1117/12.2274719
  • Link: https://doi.org/10.1117/12.2274719
  • Department: Department of Radioelectronics
  • Annotation:
    Camera response function (CRF) is widely used for the description of the relationship between scene radiance and image brightness. Most common application of CRF is High Dynamic Range (HDR) reconstruction of the radiance maps of imaged scenes from a set of frames with different exposures. The main goal of this work is to provide an overview of CRF estimation algorithms and compare their outputs with results obtained under laboratory conditions. These algorithms, typically designed for multimedia content, are unfortunately quite useless with astronomical image data, mostly due to their nature (blur, noise, and long exposures). Therefore, we propose an optimization of selected methods to use in an astronomical imaging application. Results are experimentally verified on the wide-field camera system using Digital Single Lens Reflex (DSLR) camera.

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.

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.

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.

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.

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.

Open source database of images DEIMOS: extension for large-scale subjective image quality assessment

  • Authors: doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: Applications of Digital Image Processing XXXVII. Bellingham: SPIE, 2014. pp. 92170J-1-92170J-8. Proceedings of SPIE. ISSN 0277-786X. ISBN 978-1-62841-244-4.
  • Year: 2014
  • DOI: 10.1117/12.2061369
  • Link: https://doi.org/10.1117/12.2061369
  • Department: Department of Radioelectronics
  • Annotation:
    DEIMOS (Database of Images: Open Source) is an open-source database of images and video sequences for testing, verification and comparison of various image and/or video processing techniques such as compression, reconstruction and enhancement. This paper deals with extension of the database allowing performing large-scale web-based subjective image quality assessment. Extension implements both administrative and client interface. The proposed system is aimed mainly at mobile communication devices, taking into account advantages of HTML5 technology; it means that participants dont need to install any application and assesment could be performed using web browser. The assessment campaign administrator can select images from the large database and then apply rules defined by various test procedure recommendations. The standard test procedures may be fully customized and saved as a template. Alternatively the administrator can define a custom test, using images from the pool and other components, such as evaluating forms and ongoing questionnaires. Image sequence is delivered to the online client, e.g. smartphone or tablet, as a fully automated assessment sequence or viewer can decide on timing of the assessment if required. Environmental data and viewing conditions (e.g. illumination, vibrations, GPS coordinates, etc.), may be collected and subsequently analyzed.

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.

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.

Video compression technique impact on efficiency of person identification in CCTV systems

  • DOI: 10.1109/CCST.2014.6987027
  • Link: https://doi.org/10.1109/CCST.2014.6987027
  • Department: Department of Radioelectronics
  • Annotation:
    Recently, High Efficiency Video Coding (HEVC or H.265) standard becomes to be widely applied and exploited. This compression standard can achieve very low video bitrates and allow deployment of mobile security cameras with wireless data transmission. The paper deals with subjective evaluation and assessment of the above mentioned standard and its impact on reliability and efficiency of person identification under very low video bitrate condition. The evaluation procedure is based upon modified test with reference when the separate reference database of persons appearing the testing video sequences is available. The reference database is a set of standard portrait photos. Results of the paper show applicability of HEVC compression standard in the security CCTV camera systems especially in comparison with earlier widely used standards as H.264.

Analysis of brightness profiles during eccentric photorefraction - comparison of pupil localization algorithms

  • Authors: Jindra, T., doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: 21th Annual Conference Proceedings Technical Computing Prague 2013. Praha: Humusoft, 2013. ISSN 2336-1662. ISBN 978-80-7080-863-4.
  • Year: 2013
  • Department: Department of Radioelectronics
  • Annotation:
    Estimation of accommodative state of the human eye by eccentric photorefraction is quick and easy videometric measurements. The results can be used for evaluation of response accommodation eyes while watching the spatial stimuli in multimedia or measurement in ophthalmology. The important part is videometric data analysis and localization of the pupil in the acquired image. The accuracy of localization of the pupil in the image is a prerequisite for subsequent analysis. Time consumption of algorithms significantly affects usability of the methods in real-time processing and goal is to minimize computing time while maintaining high accuracy. Paper presents comparison of the accuracy of localization and time-consuming of 5 different image segmentation methods – circular Hough transform, Gabor wavelet convolution filtering, Daugman method, gradient method and Starburst algorithm.

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.

GRBS Followed-up by the BOOTES network

  • Authors: Guziy, S., Castro-Tirado, A., Jelínek, M., Gorosabel, J., Kubánek, P., Cunniffe, R., prof. RNDr. René Hudec, CSc., doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: Gamma-ray Bursts: 15 Years of GRB Afterglows – Progenitors, Environments and Host Galaxies from the Nearby to the Early Universe. Les Ulis: EDP Sciences, 2013. pp. 251-254. EAS Publications Series. ISSN 1633-4760. ISBN 978-2-7598-1002-4.
  • Year: 2013
  • DOI: 10.1051/eas/1361038
  • Link: https://doi.org/10.1051/eas/1361038
  • Department: Department of Radioelectronics
  • Annotation:
    The Burst Observer and Optical Transient Exploring System (BOOTES), is a global robotic observatory network, which started in 1998 with Spanish leadership devoted to study optical emissions from gamma ray bursts (GRBs) that occur in the Universe. We present shot history and current status of BOOTES network. The Network philosophy, science and some details of 117 GRBs followed-up are discussed.

Influence of HEVC Compression on Event Detection in Security Video Sequences

  • DOI: 10.1109/CCST.2013.6922066
  • Link: https://doi.org/10.1109/CCST.2013.6922066
  • Department: Department of Radioelectronics
  • Annotation:
    In this paper, the impact of the degree of compression by High Efficiency Video Coding (HEVC) on observers ability of detecting certain events in videos obtained by outdoor CCTV cameras is studied. This was done by extensive subjective testing. The testing was performed also for H.264/MPEG-4 Part 10 AVC compression on similar bitrates and the capabilities of detection were compared and thus the superiority of HEVC was proven. Also the threshold for encoder setting, where the increase of bit rate or decrease of quantization parameter (QP) do not improve observers ability to detect the events, was proposed.

Removing Barriers from Cities the Smart Way

  • Authors: doc. Ing. Stanislav Vítek, Ph.D., Richter, J.
  • Publication: Smart Homes 2013. Prague: Czech Technical University, 2013. pp. 11-13. ISBN 978-80-01-05399-7.
  • Year: 2013
  • Department: Department of Radioelectronics
  • Annotation:
    Movement around the city challenges many groups of people with notable obstacles. Wheelchair users, mothers with strollers, people with injured legs or otherwise in need of crutches, old people and others – let’s call them the nonconform travellers – would benefit from an interactive map that could present alternative routes to the desired destination and categorize these routes according to difficulties present. We offer such concept in this paper.

Virtual Auditory Space for Visually Impaired - Methods for Testing Virtual Sound Source Localization

  • Department: Department of Radioelectronics
  • Annotation:
    This article deals with issue of virtual sound source positioning for the purposes of acoustic navigation in unknown spaces and extends our research published last year. Navigation experiment was based on using PERSEUS assistive device. No appropriate standards in the field of performing subjective localization a navigation tests can be found. Our methods of design and evaluation of the listening and navigation tests are proposed and discussed. The following text is considered as an overview with references to our previous articles, which contain more detailed info.

Virtual Sound Source Positioning for Navigation of Visually Impaired

  • DOI: 10.21500/01247492.2583
  • Link: https://doi.org/10.21500/01247492.2583
  • Department: Department of Radioelectronics
  • Annotation:
    This paper deals with the options of creating Virtual Acoustic Space for the purposes of navigation of visually impaired people in unknown environment. The idea of acoustic navigation is based on using virtually positioned sounds presented through the headphones, which are performed to the client by camera operator. This proposal requires a closer aim on head motion effect and ability of the camera operator to lead the client by the sounds stimuli avoiding present obstacles. The presented article follows our previous research, extends first results and suggestions, and discovers new aspects necessary to be examined.

BOOTES Observation of GRB 080603B

  • Authors: Jelinek, M., Gorosabel, J., Castro-Tirado, A. J., de Ugarte Postigo, A., Guziy, S., Cunniffe, R., Kubanek, P., Prouza, M., doc. Ing. Stanislav Vítek, Ph.D., prof. RNDr. René Hudec, CSc., Reglero, V., Sabau-Graziati, L.
  • Publication: Acta Polytechnica. 2012, 52(1), 34-38. ISSN 1210-2709.
  • Year: 2012
  • Department: Department of Radioelectronics
  • Annotation:
    We report on multicolor photometry of long GRB080603B afterglow from BOOTES-1B and BOOTES-2. The optical afterglow has already been reported to present a break in the optical lightcurve at 0.12 ± 0.2 days after the trigger. We construct the lightcurve and the spectral energy distribution and discuss the nature of the afterglow.

BOVIS, the visible eye of Bootes-IR

  • Authors: Riva, A., Jelinek, M., Cunniffe, R., doc. Ing. Stanislav Vítek, Ph.D., Castro-Tirado, A.J., Riva, M., Zerbi, F.M.
  • Publication: Second Workshop on Robotic Autonomous Observatories. Bengaluru: Astronomical Society of India, 2012. pp. 25-32. Astronomical Society of India Conference Series. ISBN 978-81-922926-5-6.
  • Year: 2012
  • Department: Department of Radioelectronics
  • Annotation:
    This paper describes the design of a visible camera (BOVIS - BOotes VISible camera) to be installed at the Nasmyth focus of the BOOTES-IR telescope, operating at OSN, Granada, Spain. BOVIS will be fed by the visible light produced by means of a dichroic that splits the light coming from the telescope into two channels. Visible channel ranges from 400 nm to 850 nm, while the existing infrared channel (covered by the BIRCAM camera) ranges from 900 nm to 2300 nm. The instrument is compared to the REM-ROSS2 facility (La Silla, Chile) currently in refurbishing phase. An adaptive optics option is also proposed as a possible technique to increase performance beyond the seeing limitations of the Sierra Nevada site.

Building the BOOTES world-wide Network of Robotic telescopes

  • Authors: Castro-Tirado, A. J., Jelínek, M., Gorosabel, J., Kubánek, P., Cunniffe, R., Guziy, S., Lara-Gil, O., Rabaza-Castillo, O., de Ugarte Postigo, A., Sánchez-Ramírez, R., Tello, J.C., Munoz-Martínez, V., Pérez del Pulgar, C., Castillo-Carrión, S., Castro Cerón, J. M., Mateo Sanguino, J. de T., Hudec, R., doc. Ing. Stanislav Vítek, Ph.D., de la Morena Carretero, B. A., Díaz Andreu, A., Fernández-Munoz, R., Pérez-Ramírez, D., Yock, P. A., Allen, H. W., Bond, I., Christie, G., Sabau-Graziati, L., Castro, A., Pozanenko, A., Bai, J., Fan, Y., Cui, C.
  • Publication: Second Workshop on Robotic Autonomous Observatories. Bengaluru: Astronomical Society of India, 2012. p. 313-320. Astronomical Society of India Conference Series. ISBN 978-81-922926-5-6.
  • Year: 2012
  • Department: Department of Radioelectronics
  • Annotation:
    We show the status of the BOOTES Network, which is expanding worldwide with four autonomous robotic observatories already deployed in Spain, New Zealand and China. We briefly discuss the technical as well as the scientific aspects we have already achieved and the goals we are aiming at.

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.

Cost-Effective Automatic Stereoscopic Security Video System 3DSec

  • Department: Department of Radioelectronics
  • Annotation:
    Object detecting and camera tracking in a large range of distances is still important problem in the research field of security and more recently also in the research field of assistive technologies too, when it is necessary to monitor intruders in the protected perimeter or elderly and disabled people both in hospital and at home. This paper discusses the design of an automatic stereoscopic video system using two identical pan-tilt-zoom (PTZ) cameras. A PTZ camera can provide a detailed live video of selected areas within a large potential field of view. Using two such cameras the TV system can be enriched by the possibility of estimating distances of monitored object or monitoring of two selected areas simultaneously. It means that both cameras can be jointly driven as a stereoscopic pair or can be run independently.

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.

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.

Imaging Systems in Assistive Technology

  • DOI: 10.5772/31519
  • Link: https://doi.org/10.5772/31519
  • Department: Department of Radioelectronics
  • Annotation:
    This chapter follows general overview and possible applications of such a sytems and particularly inteligent CCTV (Closed Circuit TV) surveillance systems for monitoring of handicaped people, and an aids for everyday use, utilizing multimedia means in any form.

Modeling and Evaluation of Image Quality in Wireless Surveillance Networks

  • Department: Department of Radioelectronics
  • Annotation:
    This paper studies the security image quality attained in streaming video over wireless networks under different packet error models. Wireless video sensor networks are becoming common place due to increasing crime rates and growing terrorist activities. A crucial requirement for video surveillance technology especially for real-time monitoring is that the video quality must not fall below a certain threshold so that objects and events in these videos could be identified and properly interpreted by viewers. However, the time varying transmission characteristics of the wireless channel and limited throughput can lead to poor performance of multimedia traffic over wireless networks. As a result, the end user may perceive jerky motions, frame freezes, and missing segments which may affect their ability to recognize objects and effectively analyze the scenes. An experimental set-up required for wireless network surveillance using IEEE 802. is described. The authors adopt subjective user tests to study the degree of identification of objects and events in security videos generated from camera security systems and subjected to wireless channel packet loss conditions to benchmark identification in the degraded sequences. Packet loss conditions were introduced into the sequences using NS-2 network simulator.

Notes on DSLR photometry

  • Authors: doc. Ing. Stanislav Vítek, Ph.D., Blažek, M.
  • Publication: Second Workshop on Robotic Autonomous Observatories. Bengaluru: Astronomical Society of India, 2012. pp. 231-238. Astronomical Society of India Conference Series. ISBN 978-81-922926-5-6.
  • Year: 2012
  • Department: Department of Radioelectronics
  • Annotation:
    This article describes a novel procedure for the photometric calibration of an astronomical image data taken with a consumer level digital reflex camera (DSLR). A proposed algorithm is based on the measured spectral characteristics of the sensor of a digital camera and the known spectral transparency of the filters of the target photometric system. The method should allow calibration of light curves of stars of different color indexes. This article also mentions the mathematical simulation results and the preliminary results of observations with DSLR camera.

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.

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.

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.

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.

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.

New possibilities for blind people navigation

  • Department: Department of Radioelectronics
  • Annotation:
    This paper deals with the design and implementation of the device aimed at navigation of visually impaired people. First part of the article presents a review of existing assistance devices for visually impaired, in the second part follows description of the system using low-cost input and output personal computer interfaces (joystick, video grabbers, NVIDIA 3D Vision) and description of design of novel acoustic transducers, focused for use in aids for the blind.

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.

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.

Design, Manufacturing, and Commissioning of BIRCAM (Bootes InfraRed CAMera)

  • Authors: Riva, A., Conconi, P., Castro-Tirado, A. J., Zerbi, F., Cunnife, R., Jelínek, M., doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: Advances in Astronomy. 2010, 2010(si2), 1-8. ISSN 1687-7969.
  • Year: 2010
  • DOI: 10.1155/2010/760416
  • Link: https://doi.org/10.1155/2010/760416
  • Department: Department of Radioelectronics
  • Annotation:
    This paper covers the various aspect of design, manufacturing and commissioning of the infrared camera BIRCAM, installed at BOOTES-IR, the 60 cm robotic infrared telescope at Sierra Nevada Observatory (OSN, Granada, Spain). We describe how we achieved a quality astronomical image, moving from the scientific requirements.

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.

Four Years of Real-Time GRB Followup by BOOTES-1B (2005-2008)

  • DOI: 10.1155/2010/432172
  • Link: https://doi.org/10.1155/2010/432172
  • Department: Department of Radioelectronics
  • Annotation:
    Four years of BOOTES-1B GRB follow-up history are summarised for the first time in the form of a table. The successfully followed events are described case by case. Further, the data are used to show the GRB trigger rate in Spain on a per-year basis, resulting in an estimate of 18 triggers and about 51 hours of telescope time per year for real-time triggers. These numbers grow to about 22 triggers and 77 hours per year if we include also the GRBs observable within 2 hours after the trigger.

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.

PERSEUS - Personal Help for Blind User

  • Department: Department of Radioelectronics
  • Annotation:
    Considerable part of the population has any sensory or perceptual impairment. Thanks to massive progress of multimedia and permanent increasing of power of small or miniature computer an appropriate assistive technology is accessible for almost everyone who need assistance for his life. In this paper is introduced project to help blind people. First part of the article presents a review of existing assistance devices for visually impaired, in the second part follows description of the new system using combination of human operator, video stream from the user's device and acoustic beacon to navigate user.

Modeling of Astronomical Images

  • Department: Department of Radioelectronics
  • Annotation:
    A wavelet-based method is proposed for modeling a star image form when parameters of the imaging system are unknown. It is assumed that the PSF of whole system can be described by a two-dimensional Gaussian function with one parameter. The relation between this parameter and the shape of the probability density function of the wavelet coefficient is shown. This allows us to estimate the blur parameter directly from the image itself.

A very sensitive all-sky CCD camera for continuous recording of the night sky

  • Authors: Castro-Tirado, Alberto J., Jelinek, M., doc. Ing. Stanislav Vítek, Ph.D., Kubanek, P.
  • Publication: Proceedings of SPIE - 7019 - Advanced Software and Control for Astronomy II. Washington: SPIE, 2008. ISSN 0277-786X. ISBN 978-0-8194-7229-8.
  • Year: 2008
  • DOI: 10.1117/12.789361
  • Link: https://doi.org/10.1117/12.789361
  • Department: Department of Radioelectronics
  • Annotation:
    We present a novel design of an all-sky 4096 x 4096 pixels camera, devoted to continuous observations of the sky. A prototype camera is running at the BOOTES-1 astronomical station in Huelva. (Spain) since December 2002 and a, second one is working at the BOOTES-2 station in Malaga. (Spain) since July 2004. Scientific applications are the search for simultaneous optical emission associated to gamma-ray bursts, study of meteor showers, and determination of possible areas for meteorite recovery from the reconstruction of fireball trajectories. This last application requires that at, least, two such devices for simultaneously recording the sky, at distance of the order of similar to 100 km. Fifteen GRB error boxes (13 for long/soft, events and 2 for short/hard GRBs) have been imaged simultaneously to the gamma-ray emission, but no optical emission has been detected. Bright fireballs have been also recorded, allowing the determination of trajectories. as in the case of the fireball of 30 July 2005. This device is a very promising instrument for continuous recording of the night sky with moderate angular resolution and limiting magnitude (up to R similar to 10).

A photometric redshift of z = 6.39 +/- 0.12 for GRB 050904

  • Authors: Haislip, J. B., Nysewander, M. C., Reichart, D. E., Levan, A., Tanvir, N., Cenko, S. B., Fox, D. B., Price, P. A., Castro-Tirado, A. J., Gorosabel, J., Evans, C. R., Figueredo, E., MacLeod, C. L., Kirschbrown, J. R., Jelinek, M., Guziy, S., Postigo, A. D., Cypriano, E. S., LaCluyze, A., Graham, J., Priddey, R., Chapman, R., Rhoads, J., Fruchter, A. S., Lamb, D. Q., Kouveliotou, C., Wijers, R. A. M. J, Bayliss, M. B., Schmidt, B. P., Soderberg, A. M., Kulkarni, S. R., Harrison, F. A., Moon, D. S., Gal-Yam, A., Kasliwal, M. M., prof. RNDr. René Hudec, CSc. doc. Ing. Stanislav Vítek, Ph.D. Kubanek, P., Crain, J. A., Foster, A. C., Clemens, J. C., Bartelme, J. W., Canterna, R., Hartmann, D. H., Henden, A. A., Klose, S., Park, H. S., Williams, G. G., Rol, E., O'Brien, P., Bersier, D., Prada, F., Pizarro, S., Maturana, D., Ugarte, P., Alvarez, A., Fernandez, A. J. M., Jarvis, M. J., Moles, M., Alfaro, E., Ivarsen, K. M., Kumar, N. D., Mack, C. E., Zdarowicz, C. M., Gehrels, N., Barthelmy, S., Burrows, D. N.
  • Publication: Nature. 2006, 440(7081), 181-183. ISSN 0028-0836.
  • Year: 2006
  • DOI: 10.1038/nature04552
  • Link: https://doi.org/10.1038/nature04552
  • Department: Department of Radioelectronics
  • Annotation:
    Gamma-ray bursts (GRBs) and their afterglows are the most brilliant transient events in the Universe. Both the bursts themselves and their afterglows have been predicted to be visible out to redshifts of z approximate to 20, and therefore to be powerful probes of the early Universe(1,2). The burst GRB 000131, at z = 4.50, was hitherto the most distant such event identified(3). Here we report the discovery of the bright near-infrared afterglow of GRB 050904 (ref. 4). From our measurements of the near-infrared afterglow, and our failure to detect the optical afterglow, we determine the photometric redshift of the burst to be z = 6.39(-0.12)(+0.11) (refs 5-7). Subsequently, it was measured(8) spectroscopically to be z = 6.29 +/- 0.01, in agreement with our photometric estimate. These results demonstrate that GRBs can be used to trace the star formation, metallicity, and reionization histories of the early Universe.

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.

GRB follow-up with BOOTES optical chapter 5: The Swift era

  • Authors: Jelínek, M., Castro-Tirado, A. J., Kubánek, P., doc. Ing. Stanislav Vítek, Ph.D., Postigo, A.d.U., prof. RNDr. René Hudec, CSc.,
  • Publication: Gamma-Ray Bursts in the Swift Era. Melville, New York: American Institute of Physics, 2006. p. 688-691. AIP CONFERENCE PROCEEDINGS. vol. 836. ISSN 0094-243X. ISBN 0-7354-0326-0.
  • Year: 2006
  • Department: Department of Radioelectronics
  • Annotation:
    BOOTES is a robotic system, whose primary aim is to observe gamma-ray burst prompt emission. 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 short/hard GRB 000313 error box, the detection of several optical after-glow for long/soft GRBs and the non-detection of optical emission simultaneous to the high energy emission for several GRBs (both long/soft and short/hard events). During the time of operation we have got triggers from CGRO/BATSE, BeppoSAX, HETE-2, INTEGRAL and Swift. Here we present our early detections of GRB optical emission using the 30 cm Bootes-1B telescope in the R.V and I-bands since the launch of Swift.

The bright optical flash from GRB 060117

  • DOI: 10.1051/0004-6361:20065092
  • Link: https://doi.org/10.1051/0004-6361:20065092
  • Department: Department of Radioelectronics
  • Annotation:
    We present a discovery and observation of an extraordinarily bright prompt optical emission of the GRB060117 obtained by a wide-field camera atop the robotic telescope FRAM of the Pierre Auger Observatory from 2 to 10 min after the GRB. We found rapid average temporal flux decay of alpha = -1.7 +/- 0.1 and a peak brightness R = 10.1 mag. Later observations by other instruments set a strong limit on the optical and radio transient fluxes, unveiling an unexpectedly rapid further decay. We present an interpretation featuring a relatively steep electron-distribution parameter p similar or equal to 3.0 and providing a straightforward solution for the overall fast decay of this optical transient as a transition between reverse and forward shock.

GRB 050509b: the elusive optical/nIR/mm afterglow of a short-duration GRB

  • Authors: Castro-Tirado, A. J., de Ugarte Postigo, A., Gorosabel, J., Fathkullin, T., Sokolov, V., Bremer, M., Márquez, I., Marín, A. J., Guziy, S., Jelínek, M., Kubánek, P., prof. RNDr. René Hudec, CSc., doc. Ing. Stanislav Vítek, Ph.D., Mateo Sanguino, T. J., Eigenbrod, A., Pérez-Ramírez, M. D., Sota, A., Masegosa, J., Prada, F., Moles, M.
  • Publication: Astronomy & Astrophysics. 2005, 439(2), L15-L18. ISSN 0004-6361.
  • Year: 2005
  • DOI: 10.1051/0004-6361:200500147
  • Link: https://doi.org/10.1051/0004-6361:200500147
  • Department: Department of Radioelectronics
  • Annotation:
    We present multiwavelength observations of a short duration gamma-ray burst detected by Swift ( GRB 050509b) collected between 0 seconds and similar to 18.8 days after the event. No optical, near infrared or millimetre emission has been detected in spite of the well localised X-ray afterglow, confirming the elusiveness of the short duration events. We also discuss the possibility of the burst being located in a cluster of galaxies at z = 0. 225 or beyond. In the former case, the spectral energy distribution of the neighbouring, potential host galaxy, favours a system harbouring an evolved dominant stellar population ( age similar to 360 Myr), unlike most long duration GRB host galaxies observed so far, i.e. thus giving support to a compact binary merger origin. Any underlying supernova that could be associated with this particular event should have been at least 3 magnitudes fainter than the type Ib/c SN 1998bw and 2.3 mag fainter than a typical type Ia SN.

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).

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.

Measurement and analysis of image sensors

  • Authors: doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: Proceedings of SPIE - Smart Imagers and Their Application. Washington: The International Society for Optical Engineering, 2005. p. 163-169. ISSN 0277-786X. ISBN 0-8194-5950-X.
  • Year: 2005
  • DOI: 10.1117/12.637927
  • Link: https://doi.org/10.1117/12.637927
  • Department: Department of Radioelectronics
  • Annotation:
    For astronomical applications is necessary to have high precision in sensing and processing the image data. In this time are used the large CCD sensors from the various reasons. For the replacement of CCD sensors with CMOS sensing devices is important to know transfer characteristics of used CCD sensors. In the special applications like the robotic telescopes (fully automatic, without human interactions) seems to be good using of specially designed smart sensors, which have integrated more functions and have more features than CCDs.

Modeling of IR Image Sensors

  • Authors: doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: Proceedings of Workshop 2005. Praha: České vysoké učení technické v Praze, 2005. pp. 408-409. ISBN 80-01-03201-9.
  • Year: 2005
  • Department: Department of Radioelectronics
  • Annotation:
    The finding of the optimal model of the real imaging system (including the image sensors) is constantly actual theme in an area of obtaining, processing, reproduction (visualization) and archiving of any imaging data.

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).

...

  • Authors: doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: MATLAB 2004 - Sborník příspěvků 12. ročníku konference. Praha: VŠCHT, 2004. pp. 594-596. ISBN 80-7080-550-1.
  • Year: 2004
  • Department: Department of Radioelectronics
  • Annotation:
    Pro aplikace zpracování obrazu, zejména pak vědecké aplikace, jako je astronomie či biomedicína, je velmi důležitá vysoká přesnost měření. Existuje několik způsobů jak zlepšit dosažených výsledků. Jedním z nich je dekonvoluce získaných obrazových dat s přenosovou charakteristikou obrazového systému, kterým byla data pořízena. V následujícím textu se budeme zabývat měřením takových charakteristik, jejich výpočtem a porovnáním výsledků simulací v Matlabu se změřenými charakteristikami.

...

  • Authors: doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: Seminář o řešení projektu GA ČR 102/03/H109. Brno: VUT v Brně, FEI, Ústav radioelektroniky, 2004. pp. 45-46. ISBN 80-214-2730-2.
  • Year: 2004

...

  • Authors: doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: Seminář o řešení projektu GA ČR 102/03/H109. Brno: VUT v Brně, FEI, Ústav radioelektroniky, 2004. p. 24. ISBN 80-214-2559-8.
  • 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.

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.

Color Imaging Sensors

  • Authors: doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: Mikroskopie 2004. Praha: Czech Technical University in Prague, 2004. p. 19-28. ISBN 80-01-03170-5.
  • Year: 2004

Experimental Measuring of Transfer Characteristics of Image Sensors

  • Authors: doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: 8th International Student Conference on Electrical Engineering, POSTER 2004, May 20 2004, Prague. Praha: ČVUT v Praze, FEL, 2004. pp. EI36.
  • Year: 2004
  • Department: Department of Radioelectronics
  • Annotation:
    There are differrent methods which can been used for determine the transsfer characteristics of image sensor. For example is there method involved scanning sine wave charts comprising a number of patches with different frequencies. The sesond method involved the scanning and Fourier transform of image of point source. Finally is there edge gradient method used in the past to analyse photographs taken with imaging system.

Modeling of Real Imaging Systems

  • Authors: doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: Proceedings of Workshop 2004. Praha: Czech Technical University in Prague, 2004. p. 414-415. ISBN 80-01-02945-X.
  • Year: 2004

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.

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.

Autofocusing Method Based on PSF of Imaging System

  • Authors: doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: Telecommunications and Signal Processing TSP-2003. Brno: VUT v Brně, 2003. pp. 151-154. ISBN 80-214-2433-8.
  • Year: 2003

GRB 030115, simultaneous observations by BOOTES-1

GRB 030226 simultaneous optical observations

Modeling of Imaging Systems in MATLAB

  • Department: Department of Radioelectronics
  • Annotation:
    For many applications in image processing it is necessary to know model of imaging system, which has been used for image data obtain. Knowledge about system can be used for the simulation of an image data in astronomy (telescope and CCD camera, for example in near IR band) of we can treat the compression algorithm as any other imaging system and perform objective image quality measurement.

The Effect of Image Sensor Configurations on Image Quality

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.

Image Quality Influenced by Selected Image Sensor Parameters

  • Authors: doc. Ing. Stanislav Vítek, Ph.D., Hozman, J.
  • Publication: SPIE Proceedings, Vol. 5036. Washington: SPIE, 2002. p. 14-19. ISSN 0277-786X. ISBN 0-8194-4837-0.
  • Year: 2002

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.

PSF and MTF of Imaging System Simulation

  • Authors: doc. Ing. Stanislav Vítek, Ph.D.,
  • Publication: POSTER 2002 - Book of Extended Abstracts. Praha: České vysoké učení technické v Praze, Fakulta elektrotechnická, 2002. pp. IC52.
  • Year: 2002

A Method for Searching of Gaussian Objects in Highly Noise Image

Responsible person Ing. Mgr. Radovan Suk