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Segmentation in microscopic images
T.Kovács, Matúš ; Jiřík, Radovan (referee) ; Kolář, Radim (advisor)
This thesis deals with the segmentation of microscopic images from plant sections. It describes the importance of the histogram for obtaining information from the image, and the utilization of the wavelet transformation for the preprocessing of the images. The thesis describes and categorizes different segmentation methods. In the thesis we use MATLAB for the validation of the presented theories and as the interface for creating a software model. The created software application automatically analyzes and evaluates microscopic images.
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Projection and projection-reconstruction x-ray imaging process simulation
Fiala, Petr ; Jiřík, Radovan (referee) ; Drastich, Aleš (advisor)
The work deals with physical principles of X-ray generation and development of image during projection and projection reconstruction. A proposal of user’s application in a Matlab – Guide is given, which can be used as a laboratory exercise of the simulation of the projection- and projection image reconstruction. The computer program involves an evaluation of a X-ray quality of CT RTG ZS – quantitative assessment of spatial resolution and as well as the acquisition contrast as a function on an object size. The main aim of the work was the comparison of the acquisition contrast at various acquisition projection and projection-reconstruction parameters. Also, the work is illustrated by some results achieved.
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Dynamic Focusing in Ultrasound Tomography
Kratochvíla, Jiří ; Roleček, Jiří (referee) ; Jiřík, Radovan (advisor)
The aim of the master’s thesis, is to get acquainted with the dynamic focusing in conventional ultrasound systems, to modify this method for ultrasound computer tomography and to realize and interpret this modification on simulated and real data in a transparent graphic interface. The modification of the dynamic focusing was executed for the 3D ultrasound computer tomograph developed in Karlsruhe. Simulated data, that are necessary for focusing, were generated by existing program, which was adjusted. The new created program of the dynamic focusing was tested and evaluated with those simulated and real data.
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Population models in biology
Vadkerti, Kristián ; Archalous, Tomáš (referee) ; Jiřík, Radovan (advisor)
In this work I focused on a program creation to demonstrate population models in biology, concretely in Matlab program environment. The aim of by myself created graphic interface is modeling from directly given parameters or parameters gained by appropriately chosen optimalisation methods for concreate population model type from loaded real data, whereas I efforted to create such a model, that fits the most approximately with real datas.
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Acquisition contrast of X-ray projection and projection-reconstruction imaging
Zubal, Lukáš ; Jiřík, Radovan (referee) ; Drastich, Aleš (advisor)
The work resulted in computer application which simulates X-ray projection and projection-reconstruction imaging in voxel space. Application user becomes acquainted with terms of acquisition contrast of X-ray projection and projection-reconstruction imaging. The thesis takes detailed look at algorithms of computing ray integrals and X-ray projection and projection-reconstruction imaging. The potential of modern computer graphics is also discussed.
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Multichannel Image Deconvolution
Bradáč, Pavel ; Kolář, Radim (referee) ; Jiřík, Radovan (advisor)
This Master Thesis deals with image restoration using deconvolution. The terms introducing into deconvolution theory like two-dimensional signal, distortion model, noise and convolution are explained in the first part of thesis. The second part deals with deconvolution methods via utilization of the Bayes approach which is based on the probability principle. The third part is focused on the Alternating Minimization Algorithm for Multichannel Blind Deconvolution. At the end this algorithm is written in Matlab with utilization of the NAG C Library. Then comparison of different optimization methods follows (simplex, steepest descent, quasi-Newton), regularization forms (Tichonov, Total Variation) and other parameters used by this deconvolution algorithm.
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Modeling of ultrasound field by means of finite element method
Göringer, Tomáš ; Jiřík, Radovan (referee) ; Roleček, Jiří (advisor)
The first part of the Master´s thesis describes physical principles of ultrasound and fundamental variables of ultrasound field. It also deals with mathematical description of finite element method and outlines basic principles of ultrasound computed tomography. The second part introduces finite elements generator GMSH. This part focuses on the process of ultrasound field simulation and presents software that can be used for field simulation. The last part contains examples of models.
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Measurement of ultrasound speed
Pouč, Petr ; Roleček, Jiří (referee) ; Jiřík, Radovan (advisor)
The thesis deals with the ultrasonic velocity measurement. The ultrasonic velocity was determined on basis of ultrasonic flight time from a transmitter to a receiver. Three methods how to determine the ultrasonic velocity in medium were proposed. Special algorithms have been created and later on build in the developed program. All the software was developed in Agilent VEE Pro 8.5. The thesis contains a proposal of two experiments tutorials for the department of Biomedical engineering that will be used during experimental lessons. The experiments deal with ultrasonic velocity measurement.
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Texture analysis of retinal images oriented towards detection of neronal fibre layer
Gazárek, Jiří ; Jiřík, Radovan (referee) ; Jan, Jiří (advisor)
The thesis is focused on detection of local disappearance of the neural layer on retina in fundus-camera images. The first chapter describes the human eye physiology, the glaucoma disease and the analyzed data. The second chapter compares four different approaches that should enable automatic detection of a possible damage to the retinal neural layer. These four approaches have been tested and evaluated; three of them showed an acceptable correlation with the medical expert conclusions – the directional spectral approach, the edge based approach and the difference local brightness. The last approch via local co-occurrence matrices has not turned out to be informative with the respect to the issue concerned. Then a program for the automatic detection of the nerve fibre layer loss areas has been designed, realized and evaluated. This task is solved in the last chapter. A relatively good agreement between the medical expert conclusions and the conclusions detected automatically by this program has been reached.
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Analysis of Colour Retinal Images Aimed at Segmentation of Vessel Structures
Odstrčilík, Jan ; Jiřík, Radovan (referee) ; Jan, Jiří (advisor)
Segmentation of vessel structure is an important phase in analysis of retinal images. The resulting vessel system description may be important for diagnostic of many eye and cardiovascular diseases. A method for automatic segmentation of the vessel structure in colour retinal images is presented in the thesis. The method utilises 2D matched filtering to detect presence of short linear vessel sections of a particular thickness and orientation. The approach correlates the local image areas with a 2D masks based on a typical brightness profile perpendicular to vessels of a particular width. Three different approximated profiles are used and corresponding matched filters are designed for: thin, medium and thick vessels. The evaluation of typical vessel profiles and filter design are described in chapter 3 and chapter 4. The parametric images obtained by convolution of the image with the masks are then thresholded in order to obtain binary representation of vessel structure. The three binary representations are consequently combined to provide the best available rough vessel map, which is finalised by complementing the obviously missing vessel sections and cleaning the disconnected fractional artefacts. The thresholding algorithm and final steps of processing are mentioned in chapter 5 and chapter 6. The method has been implemented by computer and the program for automatic vessel segmentation has been developed using database of real retinal images. The efficiency of the method has been finally evaluated on images from the standard database DRIVE.
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