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Correction of phase image background in the digital holographic microscope using convolution
Rudolfová, Zdena ; Malina, Radomír (referee) ; Uhlířová, Hana (advisor)
This bachelor thesis concentrates on a correction of background in the phase image of cells from a transmitted-light digital holographic microscope (TDHM). Optical aberrations in the optical systems of the object and reference arms cause "deformation" of the phase image. The cell is not displayed on a background with a constant value of phase, it is displayed on a background with phase values continuously changing between different places in the image. A method for removing the consequence of this imperfection from the image is described in this thesis. The principle lies in partial convolution of the phase image with a convolution kernel determined by a two-dimensional Gaussian function with the same variance in the both axes. To eliminate loss of information about the cells, the convolution is computed only from those parts of the phase image which contain no cells. The result of the convolution is considered to be an approximation of the background. This approximation is then subtracted from the phase image. The resulting phase image has a constant background, containing only noise. The necessary mathematical concepts are resumed in the introductory part of the thesis. The basic principle of the TDHM image reconstruction is also described. As a part of the thesis, a computer programme Odečet pozadí (Background subtraction) was created, which processes the phase images from the TDHM using this method.
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A method for the visualization of high phase gradients in a microscopic image
Druckmüllerová, Hana ; Martišek, Dalibor (referee) ; Chmelík, Radim (advisor)
Holografická mikroskopie je nekonvenční mikroskopická technika, vhodná zvláště pro vzorky s malou optickou hustotou, která umožňuje zviditelnit index lomu pozorovaných objektů. Na Ústavu fyzikálního inženýrství Fakulty strojního inženýrství VUT v Brně byl sestrojen unikátní transmisní digitální holografický mikroskop (TDHM). Pořízené snímky (hologramy) jsou zpracovány metodou založenou na Fourierově ransformaci, čímž je zrekonstruována intenzita a fáze světelné vlny procházející pozorovaným objektem. Fáze popisuje index lomu a tloušťku pozorovaného objektu. V místech, kde se mění index lomu nebo tloušťka, dochází i ke změně fáze. Úkolem této bakalářské práce bylo najít metodu pro zviditelnění míst s vysokým gradientem fáze. Podařilo se vytvořit metodu, která nevyžaduje navazování fáze, a proto je vhodná pro libovolné obrazy pořízené TDHM. Tato metoda byla implementována do počítačového programu Gradient3D, který kromě výpočtu gradientu ve dvou a třech rozměrech umožňuje i vytváření barevných obrazů, jejichž složkami jsou kombinace intenzity, fáze a gradientu. Program též umožňuje odstranění falešných gradientů v místech s nízkou intenzitou, kde je hodnota fáze nespolehlivá. Program byl testován na několika souborech hologramů pořízených TDHM při pozorování biologických vzorků.
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Analysis of computer vision and its aplication in systems of quality management
Nguyen, Cuong Manh ; Plášková, Alena (advisor) ; Urban, Jan (referee)
The main goals of my thesis is to provide closer look into issue of computer vision and its potential in quality management. The main reason for writing this thesis is to prove that there are simple methods of controling by computer vision, that even start-ups in production sector can afford. Hereafter I am compering two methods of controling. Firsty method of controling by computer vision and secondly method of controling by human eye. I am primarily focused on its cost of implementation and operation, its speed of controling units and measurement accuracy of each methods. For this purpose I use a practical simulation of control station in fictional production line to get real comparable resuts of both methods. To costruct successful simulation with relevant results it is essential to understad principles of the issue.
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Aplikace pro automatickou detekci a rozmazání SPZ ve fotografii
Vychodil, Vojtěch
Vychodil, V. Application for Detection and Blurring of a Plate Number Located in Photo. Bachelor thesis. Brno: Mendel University, 2014. This Bachelor thesis deals with the analysis of the problem of image processing. The work then implements the acquired knowledge in detection and blurring of plate numbers in photos. The theoretical part introduces and evaluates commonly used procedures and methods. The practical part includes the design of the appli-cation as well as the outline of acquired results of detection in a selected sample of the processed image data. work describes methods of image processing and their use in the process of creating the application for plate number localisation and blurring.
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ImageJ - program for scientific processing of digital images
ŠKRABAL, Miroslav
Because image analysis is a very broad topic, this thesis deals only with the use of computer vision and image analysis for common tasks solved in the scientific industry. The thesis investigated the applicability of common hardware and software tools for creating a methodology for measuring the mass area of knotweed leaves. Part of the methodology is a description of its steps, including addressing possible pitfalls that can occur during application of the methodology. Furthermore thesis contains a description of the included macro created for ImageJ analysis program and introduction to the program itself. Finally, there are presented results obtained by application of the methodology.
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Image processing of CT and MRI data for biomechanical applications
Nagy, Ivan
In the case of image processing to obtain the geometry of tissues means an image segmentation. A segmentation is a process subdividing an image into its constituent parts or objects. There are some basic ways to achieve this. For detecting intensity discontinuities (borders) edge detectors are used. They can be implemented as approximate mathematical gradient operators or derivative operators. This paper prasents comparison of edge detectors on a set of CT images of human body.
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Graphic filter library implemented in CUDA language
Peroutková, Hedvika ; Šedivá, Zuzana (advisor) ; Sedláček, David (referee)
This thesis deals with the problem of reducing computation time of raster image processing by parallel computing on graphics processing unit. Raster image processing thereby refers to the application of graphic filters, which can be applied in sequence with different settings. This thesis evaluates the suitability of using parallelization on graphic card for raster image adjustments based on multicriterial choice. Filters are implemented for graphics processing unit in CUDA language. Opacity and image merging mode can be set for filters. Various types of filters were implemented like histogram, color, convolution filters and others. Within the frame of this thesis a graphic user interface was developed, which enables filter applying and setting for chosen image, measuring time needed for filter changes and saving final image.
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Image classification on the web
Daráni, Jakub ; Rauch, Jan (advisor) ; Berka, Petr (referee)
This thesis is dealing with image classification on the web. According to the thinking about possibilities how to classify images and suggestion of features contents theory of image processing and classification. This theoretical knowledge is used by development of the software with original algorithms (image segmentation, image correlation). Using training set, estimated features values and Weka software a classifier is developed. This classifier is implemented, tested on testing set and reviewed.
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