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Merging and Correction of Photos
Trčka, Jan ; Bařina, David (referee) ; Zemčík, Pavel (advisor)
The aim of this work is to design and implement an application using an OpenCV library. This paper describes issues of correct photo merging, attempts to eliminate defects which were created in process of taking these photos and which may occur in the actual merging process.
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Lossless Image Compression
Vondrášek, Petr ; Polok, Lukáš (referee) ; Bařina, David (advisor)
The aim of this master's thesis was to design, develop and test a method for lossless image compression. The theoretical part includes a description of selected exiting methods such as RLE, MTF, adaptive arithmetic coding, color models used in LOCO-I and JPEG 2000, predictors MED, GAP and laplacian pyramid. The conclusion includes a comparison of various combinations of chosen approaches and overall efficiency compared with PNG and JPEG-LS.
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Medical Image Data Compression
Šebek, Jiří ; Bařina, David (referee) ; Kršek, Přemysl (advisor)
This thesis deals with several lossless methods of image compression. The main goal is to achieve the best compression ratio for set of medical images. This paper provides brief introduction into the data compression theory. It also contains design of image compression and description of designed compression modules implementation. Also the verifi cation of suitability of designed method for medical images compression is involved.
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Lossy Light Field Compression
Dlabaja, Drahomír ; Milet, Tomáš (referee) ; Bařina, David (advisor)
The aim of this paper is to propose, implement and evaluate a new lossy compression method for light field images. The proposed method extends the JPEG method to four dimensions and brings new ideas which lead to better compression performance. Correlation between light field views is exploited in both dimensions by four-dimensional discrete cosine transformation. The lossy part of the encoding is performed by quantization, similarly to the JPEG method. The proposed method is implemented as a program library in a C++ language. This paper compares the proposed method to JPEG, JPEG 2000 and HEVC intra image compression methods and HEVC video compression method. The results show that the proposed method outperforms the reference methods with images with a higher amount of views. HEVC video method is better for images with fewer views or for very low bitrates.
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Improvements of JPEG Format
Liška, Radek ; Polok, Lukáš (referee) ; Bařina, David (advisor)
This thesis deals with lossy still image compression algorithms used in JPEG standard. All compression steps according to this standard are described in detail. My objective is to introduce and implement improvements that would result in increased compression ratio while adhering to the structure of the standard. At the end of the thesis, the implementation is compared to standard implementation and additional possible improvements are proposed.
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Image Compression Using the Wavelet Transform
Kontra, Matúš ; Drábek, Vladimír (referee) ; Bařina, David (advisor)
Wavelet transform belongs to modern methods used to compress data. It's application modifies data in such way, that we can use and store them in much more efficient way. Focus of this thesis lies in theoretical basis required to understand this method and its implementation. Next section shifts focus to quantization and coding - operations used to further reduce size of our data, which are provided by the SPIHT algorithm.
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Comparison of Image Quality Measuring Methods
Škurla, Adam ; Klíma, Ondřej (referee) ; Bařina, David (advisor)
This thesis is aimed at image quality assessment methods and comparison of their performance regarding compression standards JPEG and JPEG 2000. First part provides information about image quality assessment basics, mentioning existing and used methods. The second part describes approach used to acquire subjective and objective rating of image quality. Further it compares obtained subjective ratings and ratings determined by objective methods. Conclusion provides an evaluation of obtained results and specification of the most suitable methods for measuring quality of images created by compression standards stated above.
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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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Image Compression Using the Wavelet Transform
Urbánek, Pavel ; Polok, Lukáš (referee) ; Bařina, David (advisor)
This thesis is focused on subject of image compression using wavelet transform. The first part of this document provides reader with information about image compression, presents well known contemporary algorithms and looks into details of wavelet compression and following encoding schemes. Both JPEG and JPEG 2000 standards are introduced. Second part of this document analyzes and describes implementation of image compression tool including inovations and optimalizations. The third part is dedicated to comparison and evaluation of achievements.
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Time-Frequency Signal Analysis
Kovačev, Radovan ; Polok, Lukáš (referee) ; Bařina, David (advisor)
The main subject of this work represents the time-frequency signal analysis. Firstly, it intends to provide the most essential theoretical background with focus on the continuous wavelet transform, where also a comparison of the key features with its close relative the short-time Fourier transform is performed. Afterwards, there follows a demonstration of the purpose with a practical example. The particular aim is to create a phase vocoder solution for modifying the length of a sound record duration and pitch shifting. Here, in this place, the functional principles, design, procedure of assembling, outputs and achieved results are well documented.
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