National Repository of Grey Literature 140 records found  beginprevious84 - 93nextend  jump to record: Search took 0.00 seconds. 
Sleep stages classification
Cikánek, Martin ; Mézl, Martin (referee) ; Potočňák, Tomáš (advisor)
The aim of this bachelor thesis was to elaborate a literature research on the topic of automatic classification of sleep stages from polysomnographic measurements and to subsequently select a way of feature extraction and quantitatively evaluate it. In the first part, the thesis deals mostly with the theory regarding the classification of sleep stages and analyzes the various possibilities of the process. This part is followed by a description of individual parts of the program, which is used for the extraction and subsequent quantitative evaluation of the features. The work is concluded by statistical evaluation of the results.
Sensing eye movement using a device BIOPAC and eyetracker Pupil
Vančurová, Johana ; Mézl, Martin (referee) ; Svozilová, Veronika (advisor)
This bachelor thesis is focused on investigation of visual reaction time of driver using eye movements acquivition. Eye movements were acquired by Biopac device and eyetracker Pupil. The main aim of this work is to compare results of own experiments with points of reference. Theoretical part dealt with anatomy, physiology of eye and describing characteristics of EOG signals. Practical part included experimental measurements to which a group of probands was involved. In the last part of this work the obtained results were compared with the points of reference.
Image registration using evolutionary algorithms
Kubalová, Eva ; Kozumplík, Jiří (referee) ; Mézl, Martin (advisor)
The diploma thesis deals with the image registration using evolutionary algorithms from metaheuristic optimization techniques which are considered recent and widely used. The frst part of the thesis contains theoretical description of components in image registration and later focuses on the ultrasound images. In that part, the thesis explains chosen evolutionary algorithms. Three optimization methods have been implemented, in particular genetic algorithm, particle swarm optimization and frey algorithm. Chosen similarity metrics for optimization are sum of squared dierences, cosine similarity and correlation coefcient. The main part of thesis includes testing of proposed methods with the evaluation of obtained results. These parameters are later used for optimization of real ultrasound sequences obtained by the contrast imaging.
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).
Optic disc detection in video sequences from video ophthalmoscope
Čermák, Marek ; Mézl, Martin (referee) ; Odstrčilík, Jan (advisor)
This work is focused on automatic detection of optic disc in retinal images. There is briefly described anatomy of human eye, principles of retinal imaging and also overview of the methods used for optic disc detection. The practical part describes developed procedures for optic disc detection, ie detection based on watershed transform, active contours and also on region growing technique. The main method of this work is the method of circular transformation, which as the only one allowed to detect the optic disc on the images of video ophtalmoscope and also on the high quality images from fundus cameras. This method was tested on three datasets. The average overlap 92,44 % was achieved for HRF dataset, 91,03 for DRIONS dataset and 77,36 for images of video ophtalmoscope.
Modelling for ultrasound perfusion imaging
Jakubík, Juraj ; Jiřík, Radovan (referee) ; Mézl, Martin (advisor)
This master thesis deals with the contrast agents and their application in the ultrasound perfusion analysis. It is focused on Bolus & Burst method which, as a combination of two approaches that have been used so far, allows an absolute quantification of perfusion parameters in the region of interest. Contrast agent concentration time sequence is modeled as a convolution of the parametrically defined arterial input function and the tissue residual funkction. Thesis discusses different mathematical models of these functions as well as the methods of the parameters estimation. The methods functionality is validated on simulated and also preclinical data.
USB Ultrasound Imaging System
Kratochvíl, Tomáš ; Mézl, Martin (referee) ; Harabiš, Vratislav (advisor)
This master thesis deals with development and construction of ultrasound diagnostical system with USB interface. The main task is to study current usage of A mode ultrasound systems and methods of their construction. Following with own design of A mode ultrasound system with usage of assigned Olympus ultrasound transducer.
X-ray Image detectors for using in microCT systems.
Papajová, Gabriela ; Malínský, Miloš (referee) ; Mézl, Martin (advisor)
Diplomová práce se zabývá detektory rentgenového záření pro mikro-CT systémy. Teoretická část zahrnuje standartní typy rentgenových detektorů a požadavky na kvalitu obrazu pro výslednou 3D rekonstrukci. V závěru jsou popsány fyzikální parametry reálných detektorů a metody jejich měření a vyhodnocení.
Acquisition, Modeling and Signal Processing in Ultrasound Perfusion Imaging
Mézl, Martin ; Kozubek, Michal (referee) ; Flusser,, Jan (referee) ; Jiřík, Radovan (advisor)
This work deals with possibilities of ultrasound perfusion analysis for the absolute quantification of perfusion parameters. In the theoretical part of this work are discussed possibilities of using of the ultrasound contrast agents and approaches for the perfusion analysis. New methods for the perfusion analysis are suggested and tested in the practical part of this work. The methods are based on convolutional model in which the concentration of the contrast agent is modeled as aconvolution of the arterial input function and the tissue residual function. The feasibility of these methods for the absolute quantification of perfusion parameters is shown on data from phantom studies, simulations and also preclinical and clinical studies. The software for the whole process of the perfusion analysis was developed for using in hospitals.
Laboratory exercise for RTG imaging systems
Kuchař, Otakar ; Macíček, Ondřej (referee) ; Mézl, Martin (advisor)
The aim of this Bachelor thesis is to study the X-ray and computed tomography. The theoretical section explains the basic physical principles, elementary particle, atom and ionizing. The following parts of the thesis deal with topics from the origin and various types of X-ray, to interaction of X-ray with tissue and X-ray detection. For computed tomography the thesis also explains data collection, the reconstruction of image using simple back projection, filtered back projection and algebraic reconstruction. In the practical part are analysed several measurements which were taken in the X-ray chamber designed for educational purposes by Leybold. The topics solve the attenuation of X-rays depending on the type and thickness of the material and the spectrum of the X-ray radiation. In the field of computerized tomography solve tasks as the change of contrast, parameters of acquisition and methods for reconstruction. The work includes prepared sample solutions to a laboratory experiments.

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