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Applications of wavelet transform in Mathematica and Sage
Novotný, Radek ; Trzos, Michal (referee) ; Rajmic, Pavel (advisor)
This thesis focuses on image processing using wavelet transform. The usage of wavelet transform is analysed especially for image compression and image noise reduction purposes. The analysis describes in detail aspects and application of the following wavelet transform methods: CWT, DWT, DTWT, 2D DWT. The thesis further explains the meaning of the mother wavelet and studies certain specific kinds of wavelets, kinds of thresholding and its purposes and also touches on the JPEG2000 standard. Mathematica and Sage software packages were used to design algorithms for image compression and image noise reduction, utilising relevant wavelet transform findings. The concluding part of the thesis compares the two software packages and results obtained using different algorithms.
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Image compression in interactive applications in digital video broadcasting
Bodeček, Kamil ; Vrba, Kamil (advisor)
Compressed images are used very frequently in interactive applications in digital video broadcasting. New methods increasing efficiency of the image transmission in digital video broadcasting networks are proposed. Adaptive spatial filtering methods have been proposed for enhancement of the visual perception of the compressed images. New optimalization method is based on application of the filtering algorithms on more compressed images (data size are reduced). Visual quality enhancement is processed in interactive application. Further, new compression methods JPEG2000 and H.264 for image compression have been analysed. Novel compound image compression method for standard and high spatial television resolution is proposed in the thesis.
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Image Compression Based on Artificial Neural Network
Vondráček, Jiří ; Pohl, Jan (referee) ; Jirsík, Václav (advisor)
The thesis is focused on the image compression based on artificial neural network with practical implementation. The objective of this thesis is to explore possibilities of an image compression by artificial neural network and analyze results. In the theoretical part of the work, the fundamentals of artificial neural network are described and basic image compression techniques are explained. In the practical part there is a brief description of the compression program, the comparison of different settings and result evaluation.
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Error Resilience Analysis for JPEG 2000
Kovalčík, Marek ; Klíma, Ondřej (referee) ; Bařina, David (advisor)
The aim of this thesis is to analyze modern image compression format of JPEG 2000. It analyzes the effect of error resilience mechanisms on image compression with different settings. The impact of using tag embedding to help repair damaged images or using compression modes to improve error resilience is examined here. Quality is evaluated by the PSNR metric that detects the similarity of compressed and reference file. Adding certain tags to the data stream or using certain compression modes should help secure the JPEG 2000 file against image reconstruction damage. To test this hipothesis, there was created a model that acidentally damage the compressed file and evaluate decompressed images. The Kakadu library, which provides efficient work with the JPEG 2000 format, is used for the work. The experimental data set consists of various photographs in uncompressed PPM format in smaller but also in higher resolutions. The result of this work is to find out which compression settings to use for which group of images to make the compression efficient and secure the best. The end of this thesis is devoted to comparison of error resilience of JPEG 2000 and CCSDS 122.0.
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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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Compression algorithms and image processing
Šimek, Josef ; Číka, Petr (referee) ; Kyselý, František (advisor)
The method of image acquisition and processing has a decisive influence on the resulting form and size of the data, which represent the image. For the correct interpretation of the image, it is necessary to understand how the data are generated. This bachelor’s thesis deals with the problem of obtaining and modification of image data. The general procedures based on the mathematical and physical principles are analyzed. Attention is focused on closer study of JPEG and JPEG2000 compression algorithms, as effective tools for reducing the volume of image data. The purpose of this thesis is to create a JPEG video codec and to test its effectiveness in data compression. Furthermore, to find and implement a method for the suppression of blocking artifacts in compressed image, which greatly reduce its quality. The implementation will use MATLAB environment, which offers wide support for working with image data. In the final part we will compare the algorithms of JPEG and JPEG2000 in the created application. We will focus on the subjective and objective evaluation of the quality of compressed images. To work with JPEG2000 format the programs Kakadu and JPEG2000 Compressor will be used.
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Using wavelet packet transformation for image compression
Kučera, Michal ; Rajmic, Pavel (referee) ; Kyselý, František (advisor)
The need for storing and transferring digital image data is still growing nowadays. The Compression is necessary to achieve effective usage of transfer and storage capacity. This Bachelor’s Thesis is concerned with compression method based on wavelet packet transform, which is derived from wavelet transform. It is focused especially on best basis search algorithms from whole wavelet packet tree. There is a comparison between 6 best basis and near-best basis search criterions by R. R. Coifman, M. V. Wickerhauser and C. Taswell in this thesis, which is achieved by using Matlab environment based program. The program was created for testing and demonstrative purpose only and that’s why it contains certain limitation such as only black and white image processing and its limited resolution. There is applied constant threshold on testing image after the several best basis criterions application. The Mean Squared Error is used for comparing outcome quality of compressed and original image. The function that acquires minimal Mean Squared Error is considered the best best-basis search criterion in term of visual quality. The results show that some of the Taswell’s functions significantly improve the visual quality of the image at the price of worse compression ratio against common Shannon entropy.
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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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JPEG 2000 Implementation
Zlatohlávek, Adam ; Klíma, Ondřej (referee) ; Bařina, David (advisor)
The aim of this thesis is to propose a image compression methods in JPEG 2000. This consists of description of techniques used in base level stadard and analyze options in encoding process. The goal is to create compression process of input image from preprocessing to own output format. In the end of paperwork are presented results of own implementation in memory consuptions and encoding performance.
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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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