National Repository of Grey Literature 19 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Contour lines to heightfield conversion
Klimeš, Jonáš ; Pelikán, Josef (advisor) ; Dupej, Ján (referee)
Title: Contour lines to heightfield conversion Author: Jonáš Klimeš Department: Department of Software and Computer Science Education Supervisor: RNDr. Josef Pelikán, Department of Software and Computer Science Education Abstract: The task of this project is to design and test algorithms for semiautomatic contour lines conversion to height field. This work tries to solve following problems: automatic connection of disconnected contour lines, adjacent paths finding, semiautomatic ordering of contour lines with user assistance, creating of terrain height field using Catmull-Rom splines or radial basis functions. A part of this thesis is an experimental application, which implements these algorithms and displays the process of conversion. Program input are in form of contour lines in SVG vector format. Output 3D meshes are in Wavefront OBJ format. Keywords: contour lines, height field, terrain
Komprese zvuku
Dupej, Ján ; Lánský, Jan (advisor) ; Obdržálek, Jan (referee)
In the last two decades multimedia have become an integral part of our lives. However, we often face the two clashing requirements - limited storage space or internet connection capacity and the demand for reasonable quality of the media. Compression makes these two requirements more compatible by reducing the amount of data neccessary to store the media. This thesis concentrates on sound, particularly lossy or perceptual compression of audio. As opposed to lossless compression schemes, perceptual coders introduce some noise to the signal to make it better compressible by lossless methods. The tradeoff is an impressive coding efficiency provided by most of these coders. The point of interest in designig a lossy audio coder is to make that damage as imperceptible as possible. This is achieved with knowledge of psychoacoustics (exploiting the imperfections of human auditory system), specifically masking thresholds, perceptual entropy, quiet thresholds and many more. This thesis explains some of these phenomena and their practical implementations in modern audio coders. Finally an overview of select modern audio coders is given, including some technical details about their operation and capabilities.
Robust feature curve detection in 3D surface models
Hmíra, Peter ; Dupej, Ján (advisor) ; Pelikán, Josef (referee)
Most current algorithms typically lack in robustness to noise or do not handle T-shaped curve joining properly. There is a challenge to not only detect features in the noisy 3D-data obtained from the digital scanners. Moreover, most of the algorithms even when they are robust to noise, they lose the feature information near the T-shaped junctions as the triplet of lines ``confuses'' the algorithm so it treats it as a plane. Powered by TCPDF (www.tcpdf.org)
Generic algorithms for polygonal mesh manipulation
Hmíra, Peter ; Kolomazník, Jan (advisor) ; Dupej, Ján (referee)
This bachelor thesis analyses algorithms working with the volume data, especially the triangle or polygon mesh. The results of the analysis are applied in the design of the generic library which can be templated with any implementa- tion of mesh satisfying requirements of the library. The library is written in C++ using the norm C++11 with assistance of the boost library. The choice of the programming language is supported by the strong emphasis on the run-time per- formance as well as the capabilities of C++ to analyze a templated code during the compile-time. Later in thesis is described the implemenation of the library, usage of the algorithms and their concepts, the purpose of the adapters - tools that allow to run algorithms over such an implementation of the mesh that is not properly designed for the algorithm. The technique used in the development of this library can be later applied in the library developement, thus adding new algorithms to the library.
CCTV system controller including motion-detection feature
Wirth, Michal ; Horáček, Jan (advisor) ; Dupej, Ján (referee)
The object of this work is to design and implement an application for managing a smaller surveillance system. There are analyzed several ways of it's possible arrangement. After then an appropriate application's architecture is designed based on discovered facts. Implemented system is introduced from user's point of view and also in a more technical sense. There is also a research of algorithms for real-time detection of moving objects within static scenes. Introduced ones are implemented, measured for their efficiency and compared with each other.
Vessel segmentation
Dupej, Ján ; Pelikán, Josef (advisor) ; Kolomazník, Jan (referee)
Title: Vessel segmentation Author: Ján Dupej Department / Institute: Department of Software and Computer Science Education Supervisor of the master thesis: RNDr. Josef Pelikán, KSVI Abstract: In this thesis we researched some of the blood vessed segmentation and visualization techniques currently available for angiography on CT data. We then designed, implemented and tested a system that allows both semi-automatic and automatic vessel segmentation and visualization. For vessel segmantation and tracking we used a region-growing algorithm that we overhauled with several heuristics and combined with centerline detection. We then automated this algorithm by automatic seed generation. The visualization part is accomplished with an adaptation of the well-known straightened CPR method that we enhanced so that it visualizes the whole cross-section of the blood vessel, instead of just one line of it. Furthermore, we used the Bishop frame to maintain minimal twist of the curve-local coordinate system along the whole vessel. Keywords: vessel segmentation, medical data analysis, volume data
Surface registrations for topology transfer in geometric morphometry
Dupej, Ján ; Pelikán, Josef (advisor) ; Telea, Alexandru C. (referee) ; Váša, Libor (referee)
Geometric morphometry serves biologists and anthropologists to rigorously and quantitatively describe shapes. These representations can be treated as a statistical sample, allowing the researchers to study its variability within groups and correlate it to other features. Geometric morphometry uses landmarks as the proxy for shape, with consistent semantics in each specimen. General triangle meshes do not have this property, and as such, semantically consistent remeshes must be created artificially. This thesis deals with the design of an algorithm that consistently resamples a set of surface models for the purpose of statistical analysis. Coherent point drift was employed to perform nonrigid registration, whose result is then used to generate a semantically consistent remeshes. This approach was successfully applied in a number of studies. As CPD is compute-intensive, we propose methods of accelerating both its initialization and processing phases. Also, an extension was introduced, that can map the deviation of the surfaces from perfect bilateral symmetry and analyze it in a sample, which is significant, among others, for quantification of pathologies. Manual trimming of the surfaces and merging datasets results in outlier regions in the individual surfaces and potentially large differences in their vertex...
Point cloud video for HoloLens
Mačák, Adrián ; Pelikán, Josef (advisor) ; Dupej, Ján (referee)
The development of virtual and augmented reality headsets opens up many possibil- ities for using these technologies in industry, entertainment and other sectors. The aim of this work is to explore the possibilities and design the applications, that will ensure that by using Microsoft Hololens v1 and Microsoft Kinect v2 there will be a possibility to capture, process, transfer and render dynamic point cloud on the HoloLens side. The functionality is divided between three applications. The first one is a desktop application on which the capturing, processing, and a server is running. The second application, the client application, provides rendering and the user interface on HoloLens side. The third application is used to test the network throughput, simulating the point cloud video transmission. This work describes the process of how to connect a sensor to the computer, looking at yourself from a bird's eye view, and the night vision that has come out of it. The results are applications that can do these in real time. 1
Using DNN for triangular network analysis in geometric morphometry
Dvořáková, Gabriela ; Pelikán, Josef (advisor) ; Dupej, Ján (referee)
The aim of this thesis is to use deep learning for the task of 3D object recognition. Deep learning has been succesfully used for three dimensional data recognition. However, most of the published work chose to represent 3D objects as a set of projected 2D pixel images or in the form of binary voxels. The main goal is to propose an alternative mapping of 3D data to the NN input. Three data representations are introduced: Treating vertex coordinates as a 1D array, projection to a 2D grid and a set of surface oblique lines crossing the sig- nificant parts of an object. All of the proposed data representations are tested for the gender classification task using NN and CNN on 3D facial models. We analyzed the impact of coordinate relativization and a new modified dataset crea- ted by extracting a nose area from original triangle meshes. Experimental results confirmed the quality of the oblique lines approach with achieved classification accuracies of 84, 2% using CNN. 1
Visualization of the difference between two triangle meshes
Horešovský, Jan ; Pelikán, Josef (advisor) ; Dupej, Ján (referee)
Visualization of the difference between two triangle meshes is useful in geometric morphometrics where the shapes of biological objects such as bones, facial symme- tries and others are studied. Existing visualizations are mostly done by encoding various difference metrics into vertex color. However, this one-dimensional infor- mation is not enough to display multiple metrics at the same time. To overcome this limitation, we implemented an algorithm which employs the techniques of vector field visualization and uses clustered 3D arrows to encode the metrics. Focusing on visual appearance, we applied it in several types of visualizations in an experimental application called MeshDiff. We also conducted a user study of both existing and new visualizations to compare their performance in various use cases and investigate the possibilities for future improvement. 1

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