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Comparison of Modern Lossy Image Compression Formats
Kalabza, Marek ; Klíma, Ondřej (referee) ; Bařina, David (advisor)
This thesis compares modern compression methods of digital images on given datasets in terms of quality. First part describes the principle of lossy compression and then compression of JPEG, Lepton, JPEG 2000, JPEG XR, WebP, BPG, HEIF, H.265 intra frame, H.264 intra frame and AV1. Second part focuses on testing, comparison of results and evaluation. It also describes quality metrics (PSNR, PSNR-YUV, SSIM), deals with possible artefacts created during compression and points out the behavior of formats after data corruption. Based on testing and measurement, it was found that the best compression format from the tested lossy image formats is the AV1 format, specifically on the high resolution dataset, the scanned document dataset, and the map dataset.
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Lossless Video Compression
Polák, Michael Adam ; Polok, Lukáš (referee) ; Bařina, David (advisor)
This thesis is describing methods of lossless video compression. It also contains the description and formulas for conversions of color models suitable for lossless compression. The last theoretical part describes context compression and entropy coding with emphasis on arithmetic coding. Following the arithmetic coder is the description and details about the implemented video codec. This codec is then tested and compared with the currently used FFV1 and Huffyuv codecs. The result of this thesis is that adding the number of contexts improves the compression ratio although it does not outperform the compression ratio of FFV1, the compression ratio of Huffuyv was always outperformed.
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Image Compression Using the Wavelet Transform
Bradáč, Václav ; Polok, Lukáš (referee) ; Bařina, David (advisor)
This work deals with image compression using wavelet transformation. At the beginning , you can find theoretical information about the best known techniques used for image compression , a thorough description of wavelet transormation and the EBCOT algorithm. A significant part of the work is devoted to the library's own implementation . Another chapter of the diploma thesis deals with the comparison and evaluation of the achieved results of the processed library with the JPEG2000 format
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Arithmetic coding on GPU
Buneev, Leonid ; Horáček, Jan (advisor) ; Kruliš, Martin (referee)
The aim of this thesis is to investigate possibilities for creating parallel arithmetic coding implementation and measure performance improvements. In the first part, short overview of Arithmetic coding with its serial implementation (FastAC by Amir Said) is presented. The thesis then describes principles of work with GPUs and identifies possibilities of algorithm improvement and parallelization. Several parallel implementations are given, with varying performance improvements and occasional drawbacks. In conclusion, thesis provides results of performance tests of our implementation, as well as discussion about feasibility of applying GPU-oriented version of algorithm instead of serial one in real-world applications. Powered by TCPDF (www.tcpdf.org)
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Visualization of lossless compression algorithms
Madeja, Jiří ; Číž, Radim (referee) ; Šilhavý, Pavel (advisor)
This thesis focuses mainly on the development of visualization software for some of the most used lossless data compression algorithms. The first part of the thesis is devoted to the theoretical findings from the lossless data compression field. The second part of the thesis deals with the description of practical development of the software using Matlab. The draft is mainly focused on creating such environment to input data which will be encoded using most common lossless data compression algorithms, the comparison based on efficiency of those algorithms and visualization of the algorithm characteristics while in the process of encoding. Last part of the thesis is focused on presenting the final result of the software development.
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Interactive web applications supporting education
Tvorogov, Ivan ; Mangová, Marie (referee) ; Rajmic, Pavel (advisor)
The project mainly aims to the development of applications for viewing lossless data compression algorithms. A theoretical part is devoted to description of theory from the area of lossless data compression algorithms and basic description of the language of HTML5, JavaScript, and CSS that will be used during the development. A practical part is focused on proposal and implementation of particular applications.
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Lossless Image Compression
Komjáthy, Gergely ; Polok, Lukáš (referee) ; Bařina, David (advisor)
This thesis deals with lossless image compression. In this paper are shown some colour models, which can be used for lossless image compression and formulas how to convert them to RGB and vica versa. You can learn predictors, how they work and discription of some of them. There is described the function of arithmetic coder, PPM coder and a brief description of Huffman coding.
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Library of Compression Algorithms
Kozák, Filip ; Kaštil, Jan (referee) ; Košař, Vlastimil (advisor)
The purpose of this bachelor's thesis is to create the Library of Compression Algorithms which operates with data in memory. There is explained the principle of compression and decompression of individual methods, described steps and solutions for potential issues of individual algorithms and practical implementation of these algorithms. In conclusion there is the comparison of results of implemented algorithms with some existing programs for data compression.
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Compression Methods Based on Context Modelling
Gach, Tomáš ; Drábek, Vladimír (referee) ; Bařina, David (advisor)
The aim of this thesis is to describe basic properties of the context-based compression methods. Modelling procedure is presented together with the principle of an arithmetic coding. Gradually the PPM, CTW, and PAQ methods are introduced together with the possible implementation of the basic PPM probability model. The performance of context-based, dictionary and the most currently used methods of data compression is being compared. Based on obtained results, the possible usage of PPM methods is summarized.
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Implementation of Statistical Compression Method
Šreibr, Jakub ; Polok, Lukáš (referee) ; Bařina, David (advisor)
In this thesis statistical methods for data compression are presented. It deals with projecting of compression process and with it's implementation in a form of program library, which is created in language C++. Description and analysis of compression methods are discussed. The results of tests, which were performed with different compression methods are demonstrated.
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