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Image watermarking
Štágl, Luboš ; Zezula, Radek (referee) ; Číka, Petr (advisor)
This diploma thesis is concerned in static pictures Security problems. That means, additional informations (watermark) are embedded to the original picture in a specific way. This complex picture structure (watermark) should be unremoval by different attacks runing processes. The main goal of this diploma thesis is realize two separated methods digital data watermarking in MATLAB program. For reason of a quite large scale of different watermarking methods are chosen at this time only two of take were choosen. First of the methods is Watermark injection in the spatial domain and the second in the freuquency domain. Both methods are set up in a special way and finish goals of the process. Expected result are, that digital picture user doesn't know about the watermarking technique was aplied on this picture and the watermarking data are the most resistant as possible as can be. These attacks were simulated in Checkmark program.
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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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Static image compression techniques
Jirounek, Matěj ; Šmirg, Ondřej (referee) ; Krajsa, Ondřej (advisor)
Bachelor’s thesis dissert on nowadays used compression technologies static image, about their keystones, advantages and disadvantages in field of application and their reciprocal comparison. Work is divided to the seven capitols, second of which handles indicative allocation data compression, third about lossless compression and their main representative and fourth chapter is about less compression picture with her advantages and disadvantages as well as about colour models. In fifth chapter there are summarized used criteria for classification picture and in sixth chapter is shownd implementation programme in environment MATLAB.
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Applications of Dictionary Learning Methods for Audio Inpainting
Ozdobinski, Roman ; Rajmic, Pavel (referee) ; Mach, Václav (advisor)
This diploma thesis discusses methods of dictionary learning to inpaint missing sections in the audio signal. There was theoretically analyzed and practically used algorithms K-SVD and INK-SVD for dictionary learning. These dictionaries have been applied to the reconstruction of audio signals using OMP (Orthogonal Matching Pursuit). Furthermore, there was proposed an algorithm for selecting the stationary segments and their subsequent use as training data for K-SVD and INK-SVD. In the practical part of thesis have been observed efficiency with training set selection from whole signal compared with algorithm for stationary segmentation used. The influence of mutual coherence on the quality of reconstruction with incoherent dictionary was also studied. With created scripts for multiple testing in Matlab, there was performed comparison of these methods on genre distinct songs.
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Lose video signal compression – quantisation
Balada, Radek ; Kratochvíl, Tomáš (referee) ; Frýza, Tomáš (advisor)
The aim of my bachelor’s thesis is a lose video signal compression. Because sequences of digital video signals typically require vast amount of electronic memory for storage, and occupy much bandwidth during the transmission, the video signals must be compressed. Several video compression standards use two-dimensional discrete cosine transform. My job is to extend one more dimension (time) and make tests of three-dimensional discrete cosine transform. I focused on video quality compared to the compression ratio. This paper also describes a technique for generating the quantisation values for three dimensional discrete cosine transform coefficients.
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Acceleration of Data Compression Algorithms Using GPU
Cacek, Pavel ; Drábek, Vladimír (referee) ; Šimek, Václav (advisor)
This bachelor's thesis is dealing with possibility of acceleration compression algorithm on graphical card. I have studied specifically the compression algorithm JPEG, which is used for compression image data. The text first introduced technology, which give access to us use computational power of graphics cards. The work is also focused on the theoretical description of the JPEG and subsequently is describe its implementation using OpenCL and NVIDIA CUDA. Finally, there is a comparison of performance this GPGPU technologies.
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Neural networks in audio signal watermarking algorithms
Kaňa, Ondřej ; Smékal, Zdeněk (referee) ; Zezula, Radek (advisor)
Digital watermarking is a technique for digital multimedia copyright protection. The robustness and the imperceptibility are the main requirements of the watermark. This thesis deals with watermarking audio signals using artificial neural networks. There is described audio watermarking method in the DCT domain. Method is based on human psychoacoustic model and the techniques of neural networks.
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Lossy Image Compression
Bařina, David ; Herout, Adam (referee) ; Sumec, Stanislav (advisor)
This thesis deals with advanced methods of lossy image compression. To the midst of these methods belong the discrete cosine transform and Haar's discrete wavelet transform. Furthermore principles of color models and algorithms used in lossless data compression are explained in this text. The purpose of this thesis is the library implementation that is based on these cognizances.
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Comparison of Lossy Image Compression Formats
Koláček, Ladislav ; Svoboda, Pavel (referee) ; Bařina, David (advisor)
This bachelor thesis deals with comparing of lossy image compression formats. The chapters describe principles of image compression and lossy formats themselves. Specifically the lossy formats JPEG, JPEG 2000, JPEG XR and WebP. The thesis includes theoretical comparison of the formats mentioned above, along with the methods used for measuring image quality. The practical part contains the results of the quality measurements of each format and description of design together with implementation of the tutorial.
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Watermarking of static images
Bambuch, Petr ; Burda, Karel (referee) ; Číka, Petr (advisor)
The thesis deals with the security of static images. The main aim is to embed the watermark into the original data so effectively, to avoid removal of the watermark with the use of simple and fast attacks methods. With developing of the watermarking techniques the technique of attacks are improved and developed also. The main aim of the attacks is to remove and devalue the hidden watermark in the image. The goal of the thesis is to check current techniques of static image watermarking and implement two methods of watermarking, which are to be tested for robustness against attacks.
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