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Visualization of Large Volumetric Data on CPU
Dlabaja, Drahomír ; Milet, Tomáš (referee) ; Španěl, Michal (advisor)
This thesis deals with the problem of displaying volumetric data that exceeds the operating memory capacity of the machine. The work describes the design of a visualization pipeline, which consists of a data structure for large volumetric data and an algorithm that visualizes such data. The proposed hierarchical data structure accelerates sampling and allows the reduction of the total amount of data that needs to be loaded into physical memory during visualization. Visualization of processed data is achieved by the ray casting method with existing optimization techniques, such as empty space skipping and early ray termination. The data structure allows up to 12x faster sampling compared to the sampling of raw large volumetric data serialized by rows. Up to 150x faster visualization of large volumetric data in near-lossless mode has been achieved compared to the fully lossless mode by utilizing the data hierarchy. The display scheme is implemented in the form of a library in C++20 language. The implementation uses acceleration by vectorization and allows easy parallelization by the user. The library provides tools for processing and visualization of large volumetric data on the CPU.
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Acceleration of 3D Image Processing Using GPU
Kozovský, Radoslav ; Klepárník, Petr (referee) ; Španěl, Michal (advisor)
p { margin-bottom: 0.21cm; direction: ltr; color: rgb(0, 0, 0); line-height: 150%; }p.western { font-family: "Times New Roman",serif; font-size: 11pt; }p.cjk { font-family: "Times New Roman",serif; font-size: 11pt; }p.ctl { font-family: "Times New Roman",serif; font-size: 12pt; } The aim of this work is to accelerate the calculation of selected 2D and 3D image filters using GPU using OpenCL. Specifically, it deals with the implementation and comparison of various variants of Sobel's edge detector and Gauss filter using global or local memory. Acceleration has been achieved on 3D filter variants. On 2D filter variants, the overhead for data transfer to and from the GPU was too high.
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Software for visualization and processing of volumetric data
Viktorínová, Michaela ; Jakubíček, Roman (referee) ; Harabiš, Vratislav (advisor)
The work summarizes the possibilities of volume data displaying. It deals with the scalar type of volume algorithms, which are then divided into techniques of indirect and direct rendering of volume data. From indirect techniques the Marching Cubes method is mentioned. Direct techniques are further divided into trivial and advanced algorithms. The practical part describes the design, implementation and evaluation of the functionality of implemented program that uses trivial methods. The overall evaluation consists of partial evaluations of the computational complexity, the memory load and the quality of final rendering while using different methods and types of input volume data.
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Vektorová segmentace objemových medicínských dat založená na Delaunay triangulaci
Španěl, Michal ; Martišek, Dalibor (referee) ; Sochor, Jiří (referee) ; Kršek, Přemysl (advisor)
Image segmentation plays an important role in medical image analysis. Many segmentation algorithms exist. Most of them produce data which are more or less not suitable for further surface extraction and anatomical modeling of human tissues. In this thesis, a novel segmentation technique based on the 3D Delaunay triangulation is proposed. A modified variational tetrahedral meshing approach is used to adapt a tetrahedral mesh to the underlying CT volumetric data, so that image edges are well approximated in the mesh. In order to classify tetrahedra into regions/tissues whose characteristics are similar, three different clustering schemes are presented. Finally, several methods for improving quality of the mesh and its adaptation to the image structure are also discussed.
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Displaying 3D Graphics in Web Browser
Sychra, Tomáš ; Pečiva, Jan (referee) ; Španěl, Michal (advisor)
This thesis discusses possibilities of accelerated 3D scene displaying in a Web browser. In more detail, it deals with WebGL standard and its use in real applications. An application for visualization of volumetric medical data based on JavaScript, WebGL and Three.js library was designed and implemented. Image data are loaded from Google Drive cloud storage. An important part of the application is 3D visualization of the volumetric data based on volume rendering technique called Ray-casting.
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Java Client for 3D Displaing of Medical Image Data
Bireš, Jiří ; Štancl, Vít (referee) ; Kršek, Přemysl (advisor)
The thesis considers use of Java language in interactive 3D displaying of medical image data. Main point is to find out advantages of using this language in medical visualisations and find suitable tools for its future usage. At the conclusion it evaluates advantages and disadvantages of used technologies and suggests possible development of the appliacation
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Medical Image Segmentation
Lipták, Juraj ; Beran, Vítězslav (referee) ; Španěl, Michal (advisor)
This thesis deals with a graph cut approach for segmentation of the anatomical structures in volumetric medical images. The method used requires some voxels to be a priori identified as object or background seeds. The goal of this thesis is implementation of the graph cut method and construction of an interactive tool for segmentation. Selected metod's behaviour is examined on two datasets with manually-guided segmentation results. Testing is in one case focused on the influence of method parameters on segmentation results, while in the other deals with method tolerance towards various signal-to-noise and contrast-to-noise ratios on input. To assess the consistency of a given segmentation with the ground-truth the F-measure is used.
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Realistic Rendering of Smoke and Clouds
Kopidol, Jan ; Žák, Pavel (referee) ; Jošth, Radovan (advisor)
This work discourses about methods of rendering volumetric data such as clouds or smoke in computer graphics and implementation of this feature to existing application. The first part is summary of techniques and tricks used in computer graphics to display such objects in scene, their pros and cons and the most used techniques of displaying volumetric data. Next part is more closely focused to choosed technique of rendering volumetric data with consideration of light behavior inside the volume (also called participating media) and basic relationships used used in computation. In following part of work there is short list of applications - renderers used to realistic rendering of scene, which are suitable for implementation of selected volumetric data rendering algorithm. Selected application - Blender is describled more deeply including its inner structure, especially rendering engine. Last part of work is dedicated to design, implementation and integration of rendering algorithm itself.
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Image Processing on GPUs
Bačík, Ladislav ; Španěl, Michal (referee) ; Smrž, Pavel (advisor)
This master thesis deals with modern technologies in graphic hardware and using their for general purpose computing. It is primary focused on architecture of unified processors and algorithm implementation via CUDA programming interface. Thesis base is to choose suited algorithm for GPU horsepower demonstration. Main aim of this work is implementation of multiplatform library offering algorithms for discrete volumetric data vectorization. For this purpose was chosen algorithm Marching cubes that is able to find surface of processed object. In created library will be contained algorithm runnable on graphic device and also one runnable on CPU. Finally we compare both variants and discuss their pros and cons.
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Endless Cave
Pospíšil, Petr ; Pečiva, Jan (referee) ; Milet, Tomáš (advisor)
The goal of this thesis is to implement an application showing an endless cave. The basis of this cave is simplex noise method. On the noise produced by this function is afterwards applied thresholding. Produced grid of points is used like input for marching tetrahedrons algorithm. This algorithm converts volumetric data to boundary representation. Phong reflection model and Bump mapping were used in the application, too, in order to improve the visual quality. The application is based on OpenGL library. The first part of the technical report contains theoretical description of mentioned methods, the second part contains description of implementation.
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