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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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Advanced objective measurement criteria applied to image compression
Šimek, Josef ; Průša, Zdeněk (referee) ; Malý, Jan (advisor)
This diploma thesis deals with the problem of using an objective quality assessment methods in image data compression. Lossy compression always introduces some kind of distortion into the processed data causing degradation in the quality of the image. The intensity of this distortion can be measured using subjective or objective methods. To be able to optimize compression algorithms the objective criteria are used. In this work the SSIM index as a useful tool for describing the quality of compressed images has been presented. Lossy compression scheme is realized using the wavelet transform and SPIHT algorithm. The modification of this algorithm using partitioning of the wavelet coefficients into the separate tree-preserving blocks followed by independent coding, which is especially suitable for parallel processing, was implemented. For the given compression ratio the traditional problem is being solved – how to allocate available bits among the spatial blocks to achieve the highest possible image quality. The possible approaches to achieve this solution were discussed. As a result, some methods for bit allocation based on MSSIM index were proposed. To test the effectivity of these methods the MATLAB environment was used.
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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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Advanced objective measurement criteria applied to image compression
Šimek, Josef ; Průša, Zdeněk (referee) ; Malý, Jan (advisor)
This diploma thesis deals with the problem of using an objective quality assessment methods in image data compression. Lossy compression always introduces some kind of distortion into the processed data causing degradation in the quality of the image. The intensity of this distortion can be measured using subjective or objective methods. To be able to optimize compression algorithms the objective criteria are used. In this work the SSIM index as a useful tool for describing the quality of compressed images has been presented. Lossy compression scheme is realized using the wavelet transform and SPIHT algorithm. The modification of this algorithm using partitioning of the wavelet coefficients into the separate tree-preserving blocks followed by independent coding, which is especially suitable for parallel processing, was implemented. For the given compression ratio the traditional problem is being solved – how to allocate available bits among the spatial blocks to achieve the highest possible image quality. The possible approaches to achieve this solution were discussed. As a result, some methods for bit allocation based on MSSIM index were proposed. To test the effectivity of these methods the MATLAB environment was used.
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