National Repository of Grey Literature 73 records found  beginprevious64 - 73  jump to record: Search took 0.00 seconds. 
Stereoscopic Navigation of a Robot
Žižka, Pavel ; Šolony, Marek (referee) ; Žák, Pavel (advisor)
This work describes 3D reconstruction using stereo vision. It presents methods for automatic localization of corresponding points in both images and their reprojection into 3D space. Application created can be used for navigation of a robot and object avoidance. Second part of the document describes chosen components of the robot. Path finding algorithms are also discussed, particulary Voronoi's diagram.
Optoelectronic and photogrammetric measuring systems
Stančík, Petr ; Říčný, Václav (advisor)
Dissertation deals with analysis and design of optoelectronic and photogrammetric measuring systems. Specific design of optoelectronic contactless flat object area meters with analysis of attainable measurement accuracy is described. Next part is dedicated to stereophotogrammetry - principles of 3D reconstructions, methods of camera self-calibration and matching points in images are described. The analysis of attainable accuracy of monitored parameters is discussed too. Finally, the test program with implemented described routines is introduced. This test program enables practical aplication of stereophotogrammetric system for taking spatial coordinates of 3D objects.
3D microstructure evaluation of developed Si3N4 material for alloyed wire rolling applications
Lövy, Vít ; Salamon, David (referee) ; Chlup, Zdeněk (advisor)
This diploma thesis is devoted to the use of 3D reconstruction using EBSD method for microstructural analysis of silicon nitride ceramic material predetermined for the rolling-mill used in the wire production. Application of this method can be used for the grain structure reconstruction and basic microstructural parameters can be than extracted. The development of a suitable method for 3D reconstruction of the structure of the materials the main aim of this work. There are described the different steps begun by sample preparation from the investigated material trough the optimisation of analysis parameters up to the visualization of the grain structure. New type of sample geometry has been designed which leads to the better and faster observation of the microstructure of ceramic materials. This thesis also describes optimal reconstruction parameters such as the geometry of the assembly used in the microscope without mechanical movement of the sample or the influence of conductive coating prepared via in-situ sputtering of suitable metal, or adjustment of the electron and ion beams. Further are described two options of software which can be used for the final generation of 3D structure information and are assessed their advantages and disadvantages. The effect of the filter setting and other parameters and their influence on the resulting structural parameters are also evaluated.
3D reconstruction
Musálek, Martin ; Horák, Karel (referee) ; Richter, Miloslav (advisor)
Thesis solves 3D reconstruction of an object by method of lighting by pattern. A projector lights the measured object by defined pattern and two cameras are measuring 2D points from it. The pedestal of obejct rotates and during the measure are acquired data from different angles. Points are indentified from measured images, transformed to 3D using stereovision, connected to 3D model and displayed.
Stereo image processing and visualisation
Karásek, Miroslav ; Richter, Miloslav (referee) ; Petyovský, Petr (advisor)
This thesis deals with the processing of stereo images. It described the principles of calibration and rectification of stereo images. The thesis described several methods for finding important points. SURF method is then implemented for practical solution. Finding correspondences is realized using the methods of image processing library OpenCV. Reconstructed spatial coordinates of points and write by the format specified VRML97. Finally, there is introduced evaluated accuracy of spatial data acquisition and comparison of computational cost generated programs.
3D data processing
Babinec, Tomáš ; Janáková, Ilona (referee) ; Richter, Miloslav (advisor)
The thesis falls within the field of computer vision. It describes the development of the software environment for 3D data processing. The thesis deals with the design of C++ classes suitable for scene description and representation of bonding conditions between scenes elements. There is also discussed the solution of camera calibration, geometric distortion identification and 3D coordinates reconstruction. The solving of these tasks is augmented with planarity and linearity conditions, which support projection equations and augment the computational ability of the environment.
Stress relaxation in partially pyrolysed SiOC materials
Halasová, Martina ; Chlup, Zdeněk ; Černý, Martin ; Strachota, Adam ; Dlouhý, Ivo
This paper focuses on the difficulty with Vickers hardness evaluation of SiOC materials. To evaluate it, diagonals of an indent are crucial. Due to stress relaxation in experimental material it was not possible to evaluate it in the whole range of experimental temperatures. As experimental materials were used two types of commercialy available polysiloxane resins, pyrolysed in range from 400 to 1000°C.
3D diagnostika koherentních struktur ve volném proudu plazmatu
Hlína, Jan ; Sekerešová, Zuzana ; Šonský, Jiří
Optical radiation of a thermal plasma jet was recorded by a fast - shutter CCD camera through an optical system providing two perpendicular and simultaneous views of the jet. The measuring system yielded series of plasma jet images containing 8 pictures with exposure times 400 ns and intervals 7 us. The evaluation of the records was based on reconstructing the distribution of plasma optical radiation in planes perpendicular to the plasma jet axis by the inverse Radon transform. A repetitive application of this transform along the axis of the jet yielded the complete 3D distribution of the optical emission in the plasma jet. The differences between the resulting 3D matrices representing the optical intensities derived from adjacent pictures in the recorded series was used for the identification of coherent structures as regions characterized by the temporal increase or decrease of the optical emission.
Zpracování snímků výbrusů za účelem 3d rekonstrukce pórovitých materiálů
Hejtmánek, Vladimír ; Čapek, P. ; Brabec, Libor ; Zikánová, Arlette ; Kočiřík, Milan
The technique of electron microscopy in SEM/BSE work modes was compared for the purpose of porosity estimation of some porous materials such as potential membrane supports on the basis of a-alumina. To prepare casts, an individual samples were impregnated by epoxide resin AralditO under high vacuum. Every cast was cut, grinded and polished to achieve its smooth face for observation by means of electron microscopy.
Kvantifikace struktury žárovových nástřiků s pomocí objemové rekonstrukce
Ctibor, Pavel ; Lechnerová, R. ; Hofmann, P.
The paper introduces a way to study structure of thermally sprayed coatings in detail. Two microstructures are compared, which originate from two different spraying techniques used for the same material. The material selected is stainless steel AISI 316L and the techniques are plasma spraying using water-stabilized plasma gun and wire arc spraying. A sophisticated analytical technique is applied which was developed for a 3D reconstruction of the architecture of thermally sprayed coatings, revealing their main characteristic structural features such as porosity and oxide phase. The technique is called 3D mapping and describes the shape of pores, their interactions, etc. It is based on optical microscopy and software treatment of microstructural images. Also it is possible to detect pores or the structural phases, provided that they can be separated by proper threshold. This method is here applied first time on wire arc sprayed coating and also on metallic coating containing oxides.

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