Petr Páta

Image Quality Evaluation in Security Imaging Systems

The subjective image quality of image or video information is a crucial item in security imaging systems. During the last five years our lab has tested and verified various approaches to the image compression for security purposes and the evaluation of subjective image quality. In the paper we discuss selected important facts related to the subjective image quality evaluation and we present some anomalous experimental behavior of image compression techniques. An object-defined approach is investigated and advantageous characteristics of chosen methods are deployed to achieve the optimal performance of the surveillance video coder. Among others, we propose to use the artificial neural network (ANN) to predict resulting image quality rating scores. The proposed quality assessment model has been trained and tested using a set of grayscale images distorted by selected image compression algorithms

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

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.

Meteor automatic imager and analyzer: system design and its parameters

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.

Subjective image quality evaluation in security imaging systems

The subjective image quality of image or video information is a crucial item in security imaging systems. During last five years our lab has tested and verified various approaches to the image compression for security purposes and the evaluation of subjective image quality. In the paper, we have discussed selected important facts related to the subjective image quality evaluation and we have presented some anomalous experimental behavior of image compression techniques. An object-defined approach is investigated and advantageous characteristics of chosen methods are deployed to achieve the optimal performance of the surveillance video coder. Among others, we propose to use the artificial neural network (ANN) to predict resulting image quality rating scores. The proposed quality assessment model has been trained and tested using a set of grayscale images distorted by selected image compression algorithms.

Efficient method for security image data compression

We devote to the further development of our tests in the field of image compression for security purposes. This phase has been oriented to the application of Karhunen-Loeve Transform (KLT) for efficient coding of car plate images. The car plate is a special class of images and the KLT is well matched to this purpose. A set of car plates was recorded and the suboptimal coding base was generated. Applying this base some examples of car plate images have been compressed and the compression results are presented including the dependence of compression rate vs MSE. The compressed standard image test LENA is also shown for comparison. The suggested efficient compression is design to be applied in various car identification systems such as entrance gates, highway entries etc. Finally the results are discussed.

Space Variant Point Spread Function Modeling for Astronomical Image Data Processing

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

Objective and subjective image quality evaluation for security technology

The paper is devoted to the impacts of image compression algorithms on security image data. It compares three fundamentally different evaluation techniques of image objective criteria, subjective criteria and identification. We have selected two typical security image data (a car plate and a face) with different initial quality and we applied three different compression techniques-two professional (JPEG and LuRaWave-LWF) and one implemented (Karhunen-Loeve transform, KLT). A set of compressed images differing in compression rate was derived from each original image data. Finally the MSE as an objective criterion, the subjective image quality according to the ITU-R Rec. 500 and the identification measure were evaluated and compared.

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

VZLUSAT-1 nanosatellite (scheduled launch in spring 2017 from India) is a CubeSat mission which, besides other instrumentation, contains X-ray desk to perform efficiency tests of the X-ray optics. In this article the analysis of potential observational candidates for VZLUSAT-1 X-ray board is presented together with the suggestion of observational modes, laboratory measurements, and estimations of exposure settings.

Double-Station Automatic Video Observation of the Meteors

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.

Stellar objects identification using wide-field camera

This paper deals with evaluation and processing of astronomical image data, which are obtained by a wide-field all-sky image analyzing monitoring system (WILLIAM). The WILLIAM is an additional experimental camera for project MAIA equipped with wide field lens. The system can detect stellar objects as faint as 6th magnitude. Acquired image data are processed by an algorithm for stellar object detection and identification which is based on coordinates transfer function. Cartesian coordinates at the image data are transformed to horizontal coordinate system. This coordinate system allows searching in astronomical catalogues of stellar objects. This paper presents the components of WILLIAM, its measured electro-optical characteristics and some results of identification.