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Methods of object skeletonization in biomedical images
Matejčík, Martin ; Odstrčilík, Jan (referee) ; Jakubíček, Roman (advisor)
This thesis deals with the skeletonization of binary objects in 2D images. It describes the principles, approaches and uses of skeletonization. The functioning of the Lee, Zhang, Guo-Hall, and Medial Axis Transform methods is also theoretically explained. A custom image dataset consisting of biomedical and non-biomedical images of different topological levels was created. The image dataset was subjected to skeletonization by all of the selected methods. Experiments were designed to investigate the behavior of skeletonization under the influence of boundary noise and rotation. New modified images from the original dataset were created for individual experiments. The results indicated a degraded quality of skeletons from images affected by medium and high boundary noise. The methods showed robustness to rotation only at rotation angles of 90, 180 and 270 degrees, with the best results produced by Medial axis transform method. The calculation time of individual methods was also monitored depending on the increasing number of pixels in the image. The Guo-Hall method produced interesting results, but was also the slowest.
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Warehouse Modeling Using Graphical User Interface
Rajnoha, Martin
This paper describes a new algorithm which enable efficient conversion of graphical representation of warehouse into graph theory representation and consequently accelerates estimation for route costs. The proposed algorithm computes route distances between any place in warehouses and does so significantly faster than traditional approaches. For this purpose an algorithm based on Breadth first search, image processing “skeletonization” and Dijkstra algorithm was proposed. Using the proposed algorithm it is possible to search routes in a warehouse effectively and fast using precomputed routing table. Searching time is approximately hundreds of microseconds using routing table and even it is independent on size of warehouse instead of using Dijkstra algorithm.
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Conversion of Raster-Curve into Vector Representation
Král, Jiří ; Sumec, Stanislav (referee) ; Beran, Vítězslav (advisor)
In my process of tracing I deal with converting an input grayscale image into a vector one trying to keep as big similarity with the input image as possible. Tracing is carried out with the help of curve approximation even if the approximation is possible only with line elements, that is to say the curve in raster. Therefore it is necessary to extract the line elements from the input image. We can do it in two different ways according to two different objects in the image. The first group is represented by thin, ablong objects which are substituted by their skeleton. The second group is represented by large objects which are susbstituted by their contour. The found lines are then divided into such parts which can be easily curve approximated. Resulting curves are then only depicted into the output by suitable raster method.
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Bifurcation Localization in Retina Images
Kvapilová, Aneta ; Drahanský, Martin (referee) ; Semerád, Lukáš (advisor)
This thesis deals with processing images of human retina. Its main goal is to create a system which is able to localize places important in a process of creating biometrical template - bifurcations and crossing of blood vessels. The first part focuses on biometrics in detail and explains certain concepts of this area. It also mentions the anatomy of the human eye focusing on retina. The second part provides detailed description of all the stages and algorithms that were necessary in the process of creation of the application.
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Automatic rotational alignment of head CT scans
Karmazinová, Inna ; Kolář, Radim (referee) ; Jakubíček, Roman (advisor)
The aim of this thesis is automatic alignment of head CT scan. Currently, the alignment is performed manually by an expert, however this process is time consuming. Therefore, methods for automatization of this process are being developed. Two algorithms for alignment in axial and coronal plane were designed based on bilateral symmetry of head. Following an algorithm for alignment in sagittal plane which uses CG-TOB reference line for rotation angle detection. Algorithms were implemented in MATLAB and tested and validated using a database of manually annotated head CT scans.
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Warehouse modeling using graphical user interface
Rajnoha, Martin ; Mašek, Jan (referee) ; Burget, Radim (advisor)
Master’s thesis proposes a new algorithm which enables efficient conversion of graphical representation of warehouse into graph theory representation and consequently accelerates estimation for route costs. The proposed algorithm computes route distances between any places in warehouse based on Breadth first search, image processing „skeletonization“ and Dijkstra algorithm. Using the proposed algorithm it is possible to search routes in a warehouse effectively and fast using precomputed routing table. Searching time is less then milisecond using routing table and even size of warehouse doesn’t affect it significantly instead of using Dijkstra algorithm.
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Handwriting recognition using neural network
Petr, Martin ; Surynek, Pavel (advisor) ; Pergel, Martin (referee)
Title: Handwriting recognition using neural network Author: Martin Petr Department: Department of Theoretical Computer Science and Mathematical Logic Supervisor: RNDr. Pavel Surynek, PhD. Supervisor's e-mail address: pavel.surynek@mff.cuni.cz Abstract: Pattern recognition finds its use in many fields whose development has been affected by computer science and computer technology. Among these, the conversion of handwritten or printed text into computer-encoded text has a particularly prominent position. In the presented work we propose a method for recognizing handwritten characters in real-time using feedforward neural network as the basic classification mechanism. Dealing with differences among individual instances of each handwritten character we thoroughly explored the possibility of suppressing these while emphasizing characteristics that are essential for successful recognition. For these purposes we employed discrete cosine transform, whose time-proven application in audio and video signal processing or even directly in the field of pattern recognition provided a convincing argument for us to use it in our work as well. As a means of suppressing variations among various writing instruments we proposed preprocessing of input images using binarization and skeletonization. The designed method was...
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Automatic rotational alignment of head CT scans
Karmazinová, Inna ; Kolář, Radim (referee) ; Jakubíček, Roman (advisor)
The aim of this thesis is automatic alignment of head CT scan. Currently, the alignment is performed manually by an expert, however this process is time consuming. Therefore, methods for automatization of this process are being developed. Two algorithms for alignment in axial and coronal plane were designed based on bilateral symmetry of head. Following an algorithm for alignment in sagittal plane which uses CG-TOB reference line for rotation angle detection. Algorithms were implemented in MATLAB and tested and validated using a database of manually annotated head CT scans.
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Warehouse Modeling Using Graphical User Interface
Rajnoha, Martin
This paper describes a new algorithm which enable efficient conversion of graphical representation of warehouse into graph theory representation and consequently accelerates estimation for route costs. The proposed algorithm computes route distances between any place in warehouses and does so significantly faster than traditional approaches. For this purpose an algorithm based on Breadth first search, image processing “skeletonization” and Dijkstra algorithm was proposed. Using the proposed algorithm it is possible to search routes in a warehouse effectively and fast using precomputed routing table. Searching time is approximately hundreds of microseconds using routing table and even it is independent on size of warehouse instead of using Dijkstra algorithm.
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