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Directional Image Representations
Zátyik, Ján ; Rajmic, Pavel (referee) ; Průša, Zdeněk (advisor)
Various methods describes an image by specific shapes, which are called basis or frames. With these basis can be transformed the image into a representation by transformation coefficients. The aim is that the image can be described by a small number of coefficients to obtain so-called sparse representation. This feature can be used for example for image compression. But basis are not able to describe all the shapes that may appear in the image. This lack increases the number of transformation coefficients describing the image. The aim of this thesis is to study the general principle of calculating the transformation coefficients and to compare classical methods of image analysis with some of the new methods of image analysis. Compares effectiveness of method for image reconstruction from a limited number of coefficients and a noisy image. Also, compares image interpolation method using characteristics of two different transformations with bicubic transformation. Theoretical part describes the transformation methods. Describes some methods from aspects of multi/resolution, localization in time and frequency domains, redundancy and directionality. Furthermore, gives examples of transformations on a particular image. The practical part of the thesis compares efficiency of the Fourier, Wavelet, Contourlet, Ridgelet, Radon, Wavelet Packet and WaveAtom transform in image recontruction from a limited number of the most significant transformation coefficients. Besides, ability of image denoising using these methods with thresholding techniques applied to transformation coefficients. The last section deals with the interpolation of image interpolation by combining of two methods and compares the results with the classical bicubic interpolation.
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Detection of radio communication signal in frequency domain
Zátyik, Ján ; Povalač, Karel (referee) ; Maršálek, Roman (advisor)
The purpose of my bachelor’s thesis is to describe different methods of detection of radio communication signal in frequency domain. Describes principle of methods Bartlett, Welch, Multitaper, Yule-Walker and Burg for power spectrum estimation of signal. Compares simulation of methods based on described theory with methods of the software MATLAB. Firstly, performs simulation for noiseless signals OFDM, 8PSK, CDMA and finds out their usability for these signals. Secondly, repeats simulations with the same configuration of methods for noisy signals and finds out their usability for real signals.
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Dithering the image
Štefaník, Pavel ; Zátyik, Ján (referee) ; Rajmic, Pavel (advisor)
Bachelor work deals with the reducing of picture color depth by various dithering methods. These methods are compared between each other and demonstrated on various types of pictures. Each method is described and implemented in MATLAB. The results are compared from different angles: time duration of algorithm, survey based on form, my opinion and SSIM comparison.
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Exploitng sparse signal representations in capturing and recovery of nuclear magnetic resonance data
Hrbáček, Radek ; Zátyik, Ján (referee) ; Rajmic, Pavel (advisor)
This thesis deals with the nuclear magnetic resonance field, especially spectroscopy and spectroscopy imaging, sparse signal representation and low-rank approximation approaches. Spectroscopy imaging methods are becoming very popular in clinical praxis, however, long measurement times and low resolution prevent them from their spreading. The goal of this thesis is to improve state of the art methods by using sparse signal representation and low-rank approximation approaches. The compressed sensing technique is demonstrated on the examples of magnetic resonance imaging speedup and hyperspectral imaging data saving. Then, a new spectroscopy imaging scheme based on compressed sensing is proposed. The thesis deals also with the in vivo spectrum quantitation problem by designing the MRSMP algorithm specifically for this purpose.
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Interpolation with NURBS curves
Škvarenina, Ľubomír ; Rajmic, Pavel (referee) ; Zátyik, Ján (advisor)
Diploma thesis deals with image interpolation. The aim of this work is to study theoretically and then describe the nature of the various methods of image interpolation and some of them implemented in the program MATLAB. The introductory part of this work theoretically closer to important terms that are closely related to this topic of digital image processing sufficient to understand the principle. In the following of the thesis will be discussed all of today's commonly used method of image interpolation. Will hear all about the method of image interpolation using nearest neightbor interpolation and image help of polynimals such as (bi)linear, (bi)quadratic and (bi)kubic method. Then work theoretically analyzes the theory of individual species curves and splines. More specifically, coming to their most frequently used variants of B-spline curves and ther generalizations called NURBS, with addressing the problem of interpolating these curves. The final chapter consists of the results achieved in the program MATLAB.
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Modern methods of directional image representation
Mucha, Martin ; Rajmic, Pavel (referee) ; Zátyik, Ján (advisor)
Transformation methods are used to describe the image based on defined shapes, which are called bases or frames. Thanks to these shapes it is possible to transform the image with the help of calculated transformation coefficients and further work with this image. It is possible to image denoising, reconstruct the image, transform it and do other things. There are several types of methods of the image processing. In this field a significiant development could be seen. This study is focused on analysis of characteristics of individual well known methods of transformation such as Fouriers´s or Wavelet´s. For comparison, there are also new chosen methods of transformation described: Ripplet, Curvelet, Surelet, Tetrolet, Contourlet and Shearlet. Functional toolboxes were used for comparison of individual methods and their characteristics. These functional toolboxes were modified for the possibility of limitation of transformation coefficients for their potential use in subsequent reconstruction.
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Determining the optimal patch size for sparse image representation
Šuránek, David ; Zátyik, Ján (referee) ; Špiřík, Jan (advisor)
Introduction of this thesis is dedicated to the description of basic concepts and algorithms for image processing using sparse representation. Furthermore there is mentioned neural network model called Restricted Boltzmann machine, which is in the practical part of the thesis subject of behaving observation in the task of determining the optimal block size for extrapolation using K-SVD algorithm
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Image dithering methods
Škvarenina, Ľubomír ; Zátyik, Ján (referee) ; Rajmic, Pavel (advisor)
Bachelor’s thesis is concerned with the image dithering. The purpose of this report is to summarize common and latest methods of image dithering reduction including all its derivates. The important terms in close relation of this project are explained at the beginning of the report. In the next part of this bachelor’s thesis are mentioned all methods of screen dithering including all known algorythms related to these methods. This section of the report is more concerned with thresholding, random dithering and error diffusion. There are some of the methods programmed in MATLAB’s interactive environment for demonstration in ending of this paper. Then various methods are compared in terms of speed.
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Dithering the image
Štefaník, Pavel ; Zátyik, Ján (referee) ; Rajmic, Pavel (advisor)
Bachelor work deals with the reducing of picture color depth by various dithering methods. These methods are compared between each other and demonstrated on various types of pictures. Each method is described and implemented in MATLAB. The results are compared from different angles: time duration of algorithm, survey based on form, my opinion and SSIM comparison.
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Image dithering methods
Škvarenina, Ľubomír ; Zátyik, Ján (referee) ; Rajmic, Pavel (advisor)
Bachelor’s thesis is concerned with the image dithering. The purpose of this report is to summarize common and latest methods of image dithering reduction including all its derivates. The important terms in close relation of this project are explained at the beginning of the report. In the next part of this bachelor’s thesis are mentioned all methods of screen dithering including all known algorythms related to these methods. This section of the report is more concerned with thresholding, random dithering and error diffusion. There are some of the methods programmed in MATLAB’s interactive environment for demonstration in ending of this paper. Then various methods are compared in terms of speed.
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