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Advanced algorithms for compression of video sequences with ultra high resolution
Soukeník, Ondřej ; Kratochvíl, Tomáš (referee) ; Polák, Ladislav (advisor)
This bachelor thesis provides an overview of advanced video codecs and explores their applicability for compression ov videosequences in ultra high resolution (UHD). The thesis is divided into two parts, theoretical and experimental. The theoretical part of the thesis gives an overview of advanced video codecs for video compression. Furthermore, objective metrics used for evaluation of the quality of a compressed video are briefly described. This part of the thesis also contains a detailed description of the created tool, employing a reference implementation of the selected video codecs, for easy compression of video sequences in UHD. This tool is used in the experimental part to compress different video sequences. The compression efficiency of each video codec is evaluated in terms of different objective metrics. Furthermore, the Bjntegaard Delta analysis is employed to obtain infromation about the compression efficiency of the used video codecs.
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New methods for super-resolution imaging
Kučera, Ondřej ; Rajmic, Pavel (referee) ; Špiřík, Jan (advisor)
This master's thesis deals with methods of increasing the image resolution. It contens as a description of theoretical principles and description of calculations which are wellknown nowdays and are usually used for increasing image resolution both description of new methods which are used in this area of image procesing. It also contens a method which I suggested myself. There is also a description of methods for an evaluation of image similarity and a comparation of results from methods which are described in this thesis. This thesis includes implementations of selected methods in programming language MATLAB. It was created an application, which realizes some methods of increasing image and evaluate their results relation to the original image using PSNR and SSIM index.
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Methods and Tools for Image and Video Quality Assessment
Slanina, Martin ; Říčný, Václav (advisor)
Disertační práce se zabývá metodami a prostředky pro hodnocení kvality obrazu ve videosekvencích, což je velmi aktuální téma, zažívající velký rozmach zejména v souvislosti s digitálním zpracováním videosignálů. Přestože již existuje relativně velké množství metod a metrik pro objektivní, tedy automatizované měření kvality videosekvencí, jsou tyto metody zpravidla založeny na porovnání zpracované (poškozené, například komprimací) a originální videosekvence. Metod pro hodnocení kvality videosekvení bez reference, tedy pouze na základě analýzy zpracovaného materiálu, je velmi málo. Navíc se takové metody převážně zaměřují na analýzu hodnot signálu (typicky jasu) v jednotlivých obrazových bodech dekódovaného signálu, což je jen těžko aplikovatelné pro moderní komprimační algoritmy jako je H.264/AVC, který používá sofistikovené techniky pro odstranění komprimačních artefaktů. V práci je nejprve podán stučný přehled dostupných metod pro objektivní hodnocení komprimovaných videosekvencí se zdůrazněním rozdílného principu metod využívajících referenční materiál a metod pracujících bez reference. Na základě analýzy možných přístupů pro hodnocení video sekvencí komprimovaných moderními komprimačními algoritmy je v dalším textu práce popsán návrh nové metody určené pro hodnocení kvality obrazu ve videosekvencích komprimovaných s využitím algoritmu H.264/AVC. Nová metoda je založena na sledování hodnot parametrů, které jsou obsaženy v transportním toku komprimovaného videa, a přímo souvisí s procesem kódování. Nejprve je provedena úvaha nad vlivem některých takových parametrů na kvalitu výsledného videa. Následně je navržen algoritmus, který s využitím umělé neuronové sítě určuje špičkový poměr signálu a šumu (peak signal-to-noise ratio -- PSNR) v komprimované videosekvenci -- plně referenční metrika je tedy nahrazována metrikou bez reference. Je ověřeno několik konfigurací umělých neuronových sítí od těch nejjednodušších až po třívrstvé dopředné sítě. Pro učení sítí a následnou analýzu jejich výkonnosti a věrnosti určení PSNR jsou vytvořeny dva soubory nekomprimovaných videosekvencí, které jsou následně komprimovány algoritmem H.264/AVC s proměnným nastavením kodéru. V závěrečné části práce je proveden rozbor chování nově navrženého algoritmu v případě, že se změní vlastnosti zpracovávaného videa (rozlišení, střih), případně kodéru (formát skupiny současně kódovaných snímků). Chování algoritmu je analyzováno až do plného vysokého rozlišení zdrojového signálu (full HD -1920 x 1080 obrazových bodů).
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Watermarking as Document Protection
Segedy, Patrik ; Kočí, Radek (referee) ; Hanáček, Petr (advisor)
This thesis is dealing with document protection using a digital watermarking. First, a watermark characteristics are presented. Then, different usages of the watermarking are discussed. Next part of the thesis is dedicated to current development in watermarking field. It is aimed at various principles of watermark embedding into different multimedia types. Subsequently, a watermarking scheme for still images is proposed and implemented. Finally, the watermarking scheme undergoes attacks, which should damage embedded watermark. Attacked watermark is then extracted and compared to the embedded watermark.
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Quality measurement of analog and digital terrestrial television broadcasting
Zach, Ondřej ; Polák, Ladislav (referee) ; Slanina, Martin (advisor)
This bachelor‘s thesis deals with the description of basic features of the analog and digital television broadcasting and suggestion of a method for objective video quality evaluation at both broadcasting types. The base of this thesis is description of picture broadcast technology in analog and digital form. Also principles of some video quality evaluation metrics are described. In this thesis, a method for video quality comparison is suggested, including a verifying of this method. According to this method, sequences at changing broadcasting conditions were recorded for both broadcasting types. The quality factors of these sequences were computed and on the basis of these factors, the analog and digital TV broadcasting were compared.
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Performance analysis of the newest video encoding standards
Klejmová, Eva ; Polák, Ladislav (referee) ; Slanina, Martin (advisor)
The aim of this work is to describe state-of-the-art high-definition video compression algorithms. The thesis focuses on the differences between algorithms and their functionality. Procedures for video sequences compression based on reference implementations of selected codecs are being proposed and their important parameters are being discussed. Bachelor's thesis deals with comparison of reference implementations based on subjective and objective video quality measurements and time requirements. The graphic interface for selected codecs has been also designed.
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Tools for measuring video quality without reference
Zach, Ondřej ; Dostál, Petr (referee) ; Slanina, Martin (advisor)
This diploma thesis deals with objective video quality assessments without reference. Some of the basics of video quality evaluation are described. Also some basic conditions for objective video quality metrics are introduced. The main focus of the thesis are no-reference approaches. Thesis tries to describe basic methods for seeking distortion in video. The difference between spatial-domain oriented and spectral-domain oriented metrics is analyzed. We also describe design of tool for measuring objective video quality in Matlab environment. We then designed and implemented a bit-stream oriented metric for estimation of the PSNR of H.264 coded sequences. Finally, we created a database of video sequences and we held objective tests. Results were compared with results from subjective measurements.
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Comparison of compression algorithms for high definition video
Dvořák, Martin ; Polák, Ladislav (referee) ; Slanina, Martin (advisor)
Bachelor's thesis deals with comparison and analysis of various instruments of the present-day compression algorithms used to compress high-definition video. Video sequences require a large amount of memory for their storage and take up bandwidth for their transmission, so it is necessary to compress video signals with regard to the quality of video after decompressing. The work focuses mainly on the differences between the algorithms and overall performance. Part of this work is a compressed video database, comparing the performance of different algorithms and the subjective quality of compressed video.
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Comparison of Video Codecs
Urbánek, Pavel ; Svoboda, Pavel (referee) ; Bařina, David (advisor)
This thesis is aimed at analysis of video codecs and their comparison. First part of this document provides reader with the basic information on encoding and decoding process including high level description of often used algorithms. It describes codecs and the process of standardization. Second part is focused on test specifications and codecs comparsion itself including conclusion. PSNR, SSim and BD-PSNR are key methods used for comparing codecs.
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Comparison of VP9 and H.265 encoding standards
Fendrich, Vítězslav ; Boleček, Libor (referee) ; Polák, Ladislav (advisor)
This bachelor thesis deals with a comparison of the features of video coding standards VP9 and HEVC (H.265), developed to encoding videos mainly in high resolution. Theoretical part of this work is focused on the presentation and description of both VP9 and H.265 video codecs. Furthermore, objective and subjective metrics for video quality assessment are briefly described. Practical part of this work deals with an evaluation of the quality of video sequences, encoded by VP9 and H.265, with objective metrics and subjective metric. The description of the encoding process using VP9 and H.265 is also included. Proceeding of subjective tests in laboratory conditions is also described. Achieved results are clearly presented and discussed.
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