National Repository of Grey Literature 148 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Separation of dynamic and static structures in a videosequence
Serediuk, Vadym ; Pavlík, Jan (referee) ; Rajmic, Pavel (advisor)
The aim of this bachelor thesis is the description and implementation of methods for the separation of low-rank and sparse structures in image sequence, mainly focusing on methods based on convex optimization. The beginning of the work is devoted to the description of basic mathematical concepts and definitions used in the work. The next comes the description of general case of background-foreground separation in video, followed by a brief overview of existing approaches based on various mathematical models. Then, methods based on matrix decomposition are described in more detail, a convex minimization task for background separation is defined. This is followed by a practical part, where the used methods are first described and then implemented in MATLAB scripts. At the end, the analysis and comparison of the results (obtained both using own scripts and external library) is performed.
Modelling of perfusion curves in dynamic magnetic resonance
Ochodnický, Erik ; Mangová, Marie (referee) ; Rajmic, Pavel (advisor)
Perfusion MRI can provide information about perfusion characteristics of the observed tissue, which makes it a widely applicable medical procedure. Measuring process of MRI is very time-consuming, and therefore, using classical reconstruction methods, we are often not able to obtain enough samples to accomplish the needed time and space resolution for perfusion analysis. That is why it is necessary to use compressed sensing, which allows reconstruction from under-sampled data by solving an optimization model. In this work, several models for reconstruction of an image sequence are verified on real and artificial data, along with multiple algorithms capable of solving these models. Among the optimization models used in this work are two L+S models with different regularization of the S component that are solved by Forward-Backward and Chambolle-Pock algorithm. The quality of reconstruction for various models was compared especially by their perfusion curves. In the last section, we explore possible modifications of the SASS model in order to increase quality of reconstruction and resistance to under sampling for the purpose of better adaptation for dynamic data.
Separation of dynamic and static structures in a series of images
Gebrtová, Karolína ; Kosová, Petra (referee) ; Rajmic, Pavel (advisor)
This bachelor thesis is focused on the separation of static and dynamic structures of video. While the major part of the video background remains static, a few moving particles can be observed. Such video can be represented by a low-rank and a sparse component. Using a low-rank structure, the background can be separated by applying either the median filter or the dynamic mode decomposition. Furthermore, the thesis includes the robust principal component analysis which can be perceived as an optimization problem. In addition, the thesis is enhanced by result visualization methods.
Restoration of damaged audio signals using autoregressive models
Soboňa, Matúš ; Rajmic, Pavel (referee) ; Mokrý, Ondřej (advisor)
The bachelor thesis deals with the problem of restoring audio signals damaged by sample loss, using autoregressive models. The restoration itself is solved by W. Etter and A. Janssen's algorithms. These algorithms are implemented in MATLAB and tested on artificial signals aswell as on real recordings. Algorithms are then compared based on quality of restoration dependent on different parameters of signals.
Interactive web applications for image processing education
Krolop, Filip ; Záviška, Pavel (referee) ; Rajmic, Pavel (advisor)
Introduction to theory related to applets that will be used for educational purposes, creation of custom design, draft of their basic functionality and control elements, followed by own implementation and optimization. This is an interactive submission of image processing algorithms specifically, applets are focused on color models, their relationships and calculations between each other: 1 / Pallet (index) image representation, 2 / Colormixing in different models, 3 / Color image conversion to grayscale image, 4 / Conversion of a grayscale image to color image (false colors). Applets implemented using HTMLand JavaScript to demonstrate the theory and encourage students to interact.
Web applications supporting education of 2D computer graphics
Drápela, Zbyněk ; Sysel, Petr (referee) ; Rajmic, Pavel (advisor)
The bachelor thesis deals with two-dimensional computer graphics. Specifically, Bézier curves, increasing their degree without changing their shape and performing subdivision. Furthermore, the Catmull--Clark subdivision algorithm and synthesis of procedural textures. The work aimed to describe the theoretical basis of these areas and to create four web applets using JavaScript and HTML, which will be used as an aid in teaching computer graphics.
Restoration of audio signals damaged by quantization
Šiška, Jakub ; Rajmic, Pavel (referee) ; Záviška, Pavel (advisor)
This master’s thesis deals with the restoration of audio signals damaged by quantization. The theoretical part starts with a description of quantization and dequantization in general, few existing methods of dequantization of audio signals and theory of sparse representations of signals are also presented. The next part introduces algorithms suitable for dequantization, specifically Douglas–Rachford, Chambolle–Pock, SPADEQ and implementation of these algorithms in MATLAB application in the next chapter. In the last part of this thesis, testing of reconstructed signals using the algorithms takes place and results are evaluated by objective measures SDR, PEMO-Q, PEAQ and subjective listening test MUSHRA.
Adaptive Noise Cancellation Headphone
Panenka, Vojtěch ; Rajmic, Pavel (referee) ; Sysel, Petr (advisor)
The thesis deals with the analysis of technology used during the design of headphones with integrated active ambient noise cancellation and examines the possibilities of using adaptive filters to simplify development and achieve more effective attenuation.
Clean photo out of corrupted videosequence
Berky, Martin ; Záviška, Pavel (referee) ; Rajmic, Pavel (advisor)
This diploma thesis deals with separation of moving objects from static unchanging background in video sequence. Thesis contains description of common method of separation and approach based sparse signal representation. In the practical part of thesis, there were created video sequences, which are used to verify designed algorithm implemented in Matlab interface, disegned to obtain separated background from damaged video frames.
Parallelization of complex tasks in reconstruction of dynamic magnetic resonance
Bijotová, Kateřina ; Rajmic, Pavel (referee) ; Mašek, Jan (advisor)
This thesis deals with parallelization of complex tasks in reconstruction of dynamic magnetic resonance. It describes the basic principle of magnetic resonance and its relation to Fourier transform. It deals with the difference between static and dynamic magnetic resonance image reconstruction. It analyzes SVD algorithm and its use in magnetic resonance image reconstruction. It presents the principles and the importance of parallel computing in magnetic resonance imaging and describes CUDA technology. The thesis also contains a description and execution of the implementation of the reconstruction model in MATLAB and Java programming language which were optimized by JCuda library for Java implementation and gpuArray function in case of MATLAB implementation.

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