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Preprocessing of retinal images aimed at support diagnosis of glaucoma
Holásková, Anna ; Walek, Petr (referee) ; Odstrčilík, Jan (advisor)
Preprocessing of retinal images can serve as a first phase of the further image analysis or the first step preceding diagnosing of various eye diseases. The preprocessing thus represents methods of image adjustments that can improve visual characteristics of fundus images. These methods mainly include the removal of noise generated during data acquisition, contrast and brightness transformations, edge detection and thresholding. This work handles with the basic methods of image preprocessing and specific methods of preprocessing of retinal images. The preprocessing includes global illumination correction, high-pass and homomorphic filtering and adaptive enhancement of the images. Manual methods for fundus image preprocessing that are usually based on the doctor's experience can be used as well. Hence, a procedure for enhancement of retinal images using Adobe Photoshop is mentioned in this work too. Three methods for preprocessing of fundus images were selected and implemented in MATLAB programming software. These methods include homomorphic filtering, CLAHE (Contrast Limited Adaptive Histogram Equalization) and adaptive enhancement. Experimental program functions were created and tested on the available image data. Results of the selected methods are mentioned in the conclusion section. Instructions for use of implemented functions are in appendix.
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Classification of the vascular tree in fundus images
Tebenkova, Iuliia ; Kolář, Radim (referee) ; Odstrčilík, Jan (advisor)
Retinal image analysis plays a very important role, as human gets around 90% of environment information with the help of eyes. Automation of process of retinal image analysis promotes to improve the efficiency of retinal medical examinations. The following thesis is dedicated to automatic classification methods of retinal vascular system images obtained from a digital fundus camera. Vessel classification method using classifier on the base of neural networks, which is trained and then tested on the retinal vessel segments, is investigated and implemented. In this thesis anatomical retinal survey, properties of image data from digital fundus camera and retinal image classification methods are briefly described. The last chapter is devoted to the evaluation of efficiency of retinal vessel classification with automatic methods.
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Image registration of ultrasound sequences using evolutionary algorithms
Hnízdilová, Bohdana ; Odstrčilík, Jan (referee) ; Mézl, Martin (advisor)
This master´s thesis deals with the registration of ultrasound sequences using evolutionary algorithms. The theoretical part of the thesis describes the process of image registration and its optimalization using genetic and metaheuristic algorithms. The thesis also presents problems that may occur during the registration of ultrasonographic images and various approaches to their registration. In the practical part of the work, several optimization methods for the registration of a number of sequences were implemented and compared.
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Segmentation of airways in CT data
Votoupal, Pavel ; Odstrčilík, Jan (referee) ; Walek, Petr (advisor)
This thesis deals with the segmentation of lung parenchyma and extraction of airways tree from three dimensional CT scans. The external mask of the lungs is created and subsequently used to ease the process of airway segmentation. In this work, some published methods for airways segmentation are described with focus on one, which is described more in detail and also implemented in MATLAB. The proposed approach is based on morphological grayscale reconstruction. Method is tested on the real patient CT scans and finally, the results are discussed.
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Analysis of retinal nerve fiber layer for diagnosis of glaucoma
Vodáková, Martina ; Malínský, Miloš (referee) ; Odstrčilík, Jan (advisor)
The master thesis is focused on creating a methodology for quantification of the nerve fiber layer on photographs of the retina. The introductory part of the text presents a medical motivation of the thesis and mentions several studies dealing with this issue. Furthermore, the work describes available textural features and compares their ability to quantify the thickness of the nerve fiber layer. Based on the described knowledge, the methodology to make different regression models enabling prediction of the retinal nerve fiber layer thickness was developed. Then, the methodology was tested on the available image dataset. The results showed, that the outputs of regression models achieve a high correlation between the predicted output and the retinal nerve fiber layer thickness measured by optical coherence tomography. The conclusion discusses an usability of the applied solution.
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Biometry based on retinal videosequences
Oweis, Kamil ; Odstrčilík, Jan (referee) ; Kolář, Radim (advisor)
The biometric methods are the most advanced methods for recognition and verification of person identity. These methods are quite fast, safe and applicable in different situations. In this thesis is used a set of retinal scans taken with a video-ophtalmoscope. These pictures are further modified for next processing, first of all by convertion into black-andwhite binary image, in some cases was after that used a binary matrix for description of image. Afterwards was suggested comparison method of images from the database with reference image of the retina: method of overlap and shift. It was tested a set of blackand-white and then also grey images. All method calculations was realized in program Matlab of which outcome was determination of the most congruent image with reference image and evaluation of overall program accuracy.
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Precise Image Registration Used for Correction of Geometrical Image Distortion
Zemčíková, Petra ; Odstrčilík, Jan (referee) ; Mézl, Martin (advisor)
Cílem předkládané diplomové práce je pomocí lícování obrazů přesně popsat distorzní pole pro následné odstranění geometrické distorze. Snímky zkreslené geometrickou distorzí pochází z prozařovacího elektronového mikroskopu. První část práce se zabývá zejména teorií spojenou s elektronovou mikroskopií, vznikem geometrické distorze a samotnou obrazovou registrací s důrazem na intenzitní flexibilní metody lícování. Ve druhé části je pak představena vytvořená metoda pro modelování geometrické distorze a lícování obrazů postižených slabou geometrickou distorzí. Vyvinutá metoda je následně otestována na testovacích i reálných datech a srovnána s existujícími popsanými metodami pro obrazovou registraci (například open-source softwarem Elastix).
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Experimental depth of field determination of optical imaging systems
Kubáček, Svatopluk ; Čmiel, Vratislav (referee) ; Odstrčilík, Jan (advisor)
The aim of this work is to introduce the principle of scanning in optical microscopy. This thesis deals with problem of parameters of display process and their influence on the results and measurements of these parameters. In detail there is analyzed the depth of field of the optical system and there are established some possibilities of theoretical and experimental determination. Part of this thesis is the realization of the measurement work place and program providing experimental depth of field based on different measurement methods. The conclusion is devoted to the practical part, which has the task to monitor settings and optical systems and their impact on depth of field.
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Non-contact measurement and analysis of vital signs
Kolářová, Jana ; Mézl, Martin (referee) ; Odstrčilík, Jan (advisor)
The theme of this barchelor´s thesis is to process the video record of a human face to detect vital parameters - heart rate, respiratory rate were chosen. The purpose is a contactless and painless method to determine these parameters, both for the simpler gain of these data in newborns and more natural values without the influence of any subconscious fear of the devices. Or as a method of verifying work ergonomics, workplace stress, depending on the regularity of the rhythms of these parameters. The solution has been focused on testing its function and accuracy under various acquisition conditions, and has been able to reliably verify its reliability under defined scanning conditions.
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Evolution algorithms for ultrasound perfusion analysis
Kolářová, Jana ; Odstrčilík, Jan (referee) ; Mézl, Martin (advisor)
This master´s thesis is focused on the application of evolutionary algorithms for interleaving data obtained by ultrasound scanning of tissue. The interleaved curve serves to estimate perfusion parameters, thus allowing to detect possible pathophysiology in the scanned area. The theoretical introduction is devoted to perfusion and its parameters, contrast agents for ultrasonic application, ultrasonic modality scanning, optimization, evolutionary algorithms in general and two selected evolutionary algorithms - genetic algorithm and bee algorithm. These algorithms were tested on noisy data obtained from clinical images of mice with tumor. The final part summarizes the results of the practical part and provides suggestions and recommendations for further possible development.
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