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Photo conversion to black and white
Pieger, Matúš ; Boštík, Ondřej (referee) ; Richter, Miloslav (advisor)
This bachelor's thesis describes the designing of algorithms for detection, processing and conversion of desired objects from input color images to grayscale or black and white domain. The input images are divided into two groups, where the first group consists of sudoku images and other brain puzzles. The second group contains images of paper documents. The thesis analyses imperfections of input images and their effect on the building and functionality of each of the programs. Subsequently, it looks for solutions of a reliable detection of desired objects and correction of their geometric distortions. For a better readability and toner saving when printing the output images respectively, the thesis gives answers as to how to erase unwanted shadows and in which way is it possible to perform bit depth reduction to a chosen number.
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Finding of known object in a series of digital images
Bednařík, Jan ; Hasmanda, Martin (referee) ; Číka, Petr (advisor)
The aim of the thesis is detection of a known object in series of pictures. Detection is divided into two methods. First method is based on edge and color detection and comparison. Edge detection is based on detection using both Gradient and Laplacian, so on the first-order and the second-order derivative. Sobel operators were used as well as Laplacian of gaussian method. Thresholding is also used as well as autothreshold calculation. There are two variants of color detection considered in the thesis, direct color comparison and detection based on interest color search. The second part of the thesis is based on interested point detection using a modified SURF method to detect a known object in series of pictures.
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Muscle noise filtering in ECG signals
Novotný, Jiří ; Kubičková, Alena (referee) ; Smital, Lukáš (advisor)
This master's thesis deals with the optimization of numerical coefficients of the Wiener filter for muscle noise filtering in ECG signals. The theoretical part deals with ECG signal characteristic and muscle interference. It also contains a summary of the wavelet transform, wavelet Wiener's filtration, methods for calculating of the threshold and thresholding. In the last theoretical part the characteristic optimization techniques, the exhausive search and Nelder-Mead simplex method are mentioned, which were implemented in the practical part of this thesis in MATLAB. The functional verification and Wiener's filter optimization were tested on the standard electrocardiograms database CSE. By using the methods of exhausive search, the initial estimate for the solution method Nelder-Mead was obtained. The optimization method Nelder-Mead gives better results in the orders of hundredths or tenths than the method of exhausive search. The practical part is finished by the comparison of results of implemented algorithm with optimum coefficients, implemented in this thesis, with the results of other methods for filtering muscle interference in ECG signals.
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Segmentation of blood-vessels in the retinal images
Walczysko, Martin ; Kolář, Radim (referee) ; Taševský, Pavel (advisor)
This thesis deals with method of blood vessels segmentation from retinal images acquired by fundus camera. There is explored possibility of using wavelet transform as fast outline segmentation. The thesis includes study problems of preprocessing input image and decomposition of image using 2D DWT. Furthermore there is explored possibility of parametrical images thresholding that ensue from application of 2D DWT. There are designed algorithms for cleaning off artifacts from rough vessel map of blood vessel structures. The realization of algorithm was solved in programming environment MATLAB. There was created a user control interface in graphic application GUIDE, for easy control of whole segmentation process. In conclusion of thesis is proceeded the discussion of segmentation results for images from DBME database and quantitative evaluation of results for DRIVE database images.
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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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Comparative analyses of muscle activation lower extremities during running at different surface
Král, David ; Bačáková, Radka (advisor) ; Hojka, Vladimír (referee)
Title: Comparative analyses of muscle activation lower extremities during running at different surface. Objectives: The aim of this bachelor's thesis is to compare the level of activation of selected muscles of the lower extremities and the relative timing of these activations. Realize measurements on three types of surface: tartan, grass, sand and find out the differences in activations of selected muscles according to the surface. Methods: In this thesis, I used the method of analysis and the method of comparison. I applied the analysis method in the analysis of the measured signals for the running step and the comparison method in the section comparing average running step cycles from different surface types. Results: I found out that running on the tartan, acitvates all the monitored muscles in more than 75% of the average cycles within 10% of the running step time period. For softer surfaces - grass and sand, my research did not support the hypothesis, that the softer the surface is, the greater are the differences in the activation of individual muscles versus tartan. Further I found out that on sandy and grassy surfaces, the average activation time of the muscles which are more involved in stabilizing the ankle and foot, i.e. tibialis anterior and peroneus longus, increases. On a sandy...
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Ischemic thrombus analysis in multiphasic brain stroke CT data
Mikešová, Tereza ; Holeček, Tomáš (referee) ; Jakubíček, Roman (advisor)
This master thesis deals with analysis of ischemic thrombus in brain CT scans. In theoretical part, a review of methods, especially thrombus segmentation, is developed. Furthermore, the anatomy of cerebral arteries and acute ischemic stroke is summarized. Selected methods from the field of image processing are briefly described. The practical part results in a comparison of thrombus segmentation methods. The segmentation itself was preceded by data preprocessing, which is described in the theses, and the creation of a manual annotation database. The best implemented method was found to be the adaptive thresholding method, which achieved a Dice score of 0,4555. By combining the methods appropriately, a final Dice score of 0,5145 was achieved. Thrombus parameters were then calculated from the segmented volumes. The median intensity value was 51,55~HU, the median length was 15,16 mm, and the median volume was determined to be 65,34 mm3. Subsequent correlation analysis showed no significant relationship between the derived parameters.
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Detection of optic disc in retinal fundus image
Nohel, M. ; Kolář, R.
This paper presents a comparison of several image processing methods for optic disc detection in retinal images. The detection algorithms are tested on five publicly available retinal databases (total 2140 images). Thresholding, Hough transform, and matched filtering followed by postprocessing were tested for optic disc detection. It has been shown that matched filtering followed by peak detection achieves the best success rate (98.8 %).
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