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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Návrh gaussmetru s tříosou měřicí sondou / Gaussmeter design with three-axis measuring probe

Hejtmánek, Tomáš January 2018 (has links)
The purpose of this work is the design of a gaussmeter with a three-axis probe for magnetic field mapping and subsequent reconstruction of the image using magnetic impedance tomography. Commercially available gaussmeters have low bandwidth for these purposes, and signals cannot be measured in synchronous detection mode. The aim of the thesis is select the most suitable magnetic field sensors for the MIT purposes and to design the entire measuring device to meet the measurement requirements in the wider frequency band and synchronous detection. Attention will also be paid to designing a suitable mechanical design of the probe and the location of the sensors. The proposed device will be tested and evaluated for MIT purposes.
72

Segmentace měkkých tkání v obličejové části myších embryí v mikrotomografických datech / Segmentation of soft tissues in facial part of mouse embryos from X-ray computed microtomography data

Janštová, Michaela January 2019 (has links)
This diploma thesis deals with a segmentation of soft tissues in facial part of mouse embryos in Matlab. Segmentation of soft tissues of mouse embryos was not fully automated and every case needs a specific solution. Solving parts of this issues can provide valuable data for evolutionary biologists. Issues about staining and segmentation techniques are described. On the basis of accessible literature otsu thresholding, region growing, k-means clustering and segmentation with atlas were tested. In the end of this paper are those methods tested and evaluated on 3D microtomography data.
73

Zpracování tomografických dat metodou analýzy hlavních komponent pro archeologické aplikace / Processing of tomographic data by principal component analysis method for archaeological applications

Prokop, David January 2019 (has links)
Rentgenová počítačová tomografie je metoda sloužící ke 3D zobrazování vnitřní struktury objektů. Mikrostruktura objektů ukrývá důležité informace, které mohou být použity k jejich charakterizaci. Tato práce podává spojení mezi datasety získanými pomocí rentgenové počítačové mikrotomografie a oblastí statistického zpracování dat. Výstupem metody, pak bude klasifikace vzorků na základě informací o jejich mikrostruktuře. Z výsledků klasifikace vzorků, pak můžeme vyvodit různé hypotézy týkající se původu vzorků. Tato práce by mimo jiné mohla sloužit jako takový nový vhled do problematiky kombinace dat různého původu, pomocí metod statistické analýzy.
74

Kontrola kvality vstřikovaných plastů pomocí rentgenové počítačové tomografie / Quality control of injection molded plastics using X-ray computer tomography

Figar, Erik January 2020 (has links)
This Master‘s thesis deals with an aplication of computed tomography as the technology for quality control check of the plastic parts made by the injection molding process. The analyses were performed on two different types of plastic parts. These parts were delivered by two companies and they included the drawing documentation and CAD models. These plastic parts were analyzed according to their qualitative requirements. The analyses included evaluation of the geometric tolerances and porosity analysis with numerical and graphical evaluation. The new module for tool correction ,which is part of VGStudio Max, was tested on parts that were not in accordance with the required tolerances. Afterwards the new corrected geometries were exported. At the end of this Master’s thesis the porosity comparison was assessed between two different voxel resolution CT data. This comparison shows the complexity of this phenomenon and the importance of voxel resolution settings.
75

Dynamická fokusace v ultrazvukové tomografii / Dynamic Focusing in Ultrasound Tomography

Kratochvíla, Jiří January 2010 (has links)
The aim of the master’s thesis, is to get acquainted with the dynamic focusing in conventional ultrasound systems, to modify this method for ultrasound computer tomography and to realize and interpret this modification on simulated and real data in a transparent graphic interface. The modification of the dynamic focusing was executed for the 3D ultrasound computer tomograph developed in Karlsruhe. Simulated data, that are necessary for focusing, were generated by existing program, which was adjusted. The new created program of the dynamic focusing was tested and evaluated with those simulated and real data.
76

Restaurace obrazových dat z optické koherenční tomografie / Restoration of optical coherence tomography image data

Smékal, Ondřej January 2012 (has links)
Restoration of image data has become an essential part of the processing of medical images obtained by any system. The same applies in the case of optical coherence tomography. The aim of this work is to study the first restoration methods. Second, the description of the data representation from optical coherence tomography and subsequent discussions that restoration methods based on deconvolution would potentially find application in processing of Optical coherence tomography. Finally, the third to create a program solution of the OCT data restoration process in MATLAB environment and followed by discussion of effectiveness of the presented solutions.
77

Registrace CT objemových obrazů mozku pomocí globální afinní 3D transformace / Registration of volume CT brain images by means of global affine 3D transform

Mikuláš, Karol January 2012 (has links)
At present, the medical industry rapidly develops new imaging techniques and improves the imaging methods. Simultaneously also are developed new methods for processing data acquired by these methods. Especially in the past few years has become very used method of registration data, which leads to image transformations of the same scene so that the condition as possible. The work deals with the method of processing data that provides detailed information to individual structures, developments of individual structures over time, allows to simultaneously displayanatomical and physiological information or preprocessing data for further processing.
78

Afinní lícování nativních a postkontrastních CT snímků mozku / Affine registration of native and contrast-enhanced CT brain images

Chmelík, Jiří January 2013 (has links)
This thesis is dealing with problem of brain images registration aquired by computed tomography. At the beginning is explanation of image geometrical transformation methods, notably affine transformation. Following part of text the is dealing with interpolation methods issues, calculation of similarity criterion and subsequent optimalization. All issues are handled especially for three-dimensional data. Second part of this work is practical sample of MatLab® program enviroment for registration of acquired frames by affine tranformation. In this program is algorithm for removement of stair-step artefact, under head pillow and patient’s desk, too. As an optimalization algorithm is used control random search (CRS) methode. Due to medical images type, which are distributed in DICOM format, is included process for their load and save at this work.
79

Detekce optického disku ve snímcích optické koherentní tomografie / Extracting of the optic disc in optical coherence tomography images

Šeda, Jan January 2013 (has links)
The main target of this work is a design of the program for border localization of the optic disc in OCT data. Part of this program is also localization of the „optic cup“ and calculation of several values that characterize optic disc. The work is also dealing with a description of the optical coherence tomography principle which is used in ophthalmology. One chapter describes some published methods of optic cup localization. Success of the program and its comparison with OCT Zeiss Stratus 3000 is evaluated at the end of the work.
80

KALIBRACE ULTRAZVUKOVÉHO PRŮZVUČNÉHO SYSTÉMU VÝPOČETNÍ TOMOGRAFIE / CALIBRATION OF AN ULTRASONIC TRANSMISSIVE COMPUTED TOMOGRAPHY SYSTEM

Filipík, Adam January 2009 (has links)
Tato dizertace je zaměřena na medicínskou zobrazovací modalitu – ultrazvukovou počítačovou tomografii – a algoritmy zlepšující kvalitu zobrazení, zejména kalibraci USCT přístroje. USCT je novou modalitou kombinující ultrazvukový přenos signálů a principy tomografické rekonstrukce obrazů vyvíjených pro jiné tomografické systémy. V principu lze vytvořit kvantitativní 3D obrazové objemy s vysokým rozlišením a kontrastem. USCT je primárně určeno pro diagnózu rakoviny prsu. Autor spolupracoval na projektu Institutu Zpracování dat a Elektroniky, Forschungszentrum Karlsruhe, kde je USCT systém vyvíjen. Jeden ze zásadních problémů prototypu USCT v Karlsruhe byla absence kalibrace. Tisíce ultrazvukových měničů se liší v citlivosti, směrovosti a frekvenční odezvě. Tyto parametry jsou navíc proměnné v čase. Další a mnohem závažnější problém byl v pozičních odchylkách jednotlivých měničů. Všechny tyto aspekty mají vliv na konečnou kvalitu rekonstruovaných obrazů. Problém kalibrace si autor zvolil jako hlavní téma dizertace. Tato dizertace popisuje nové metody v oblastech rekonstrukce útlumových obrazů, kalibrace citlivosti měničů a zejména geometrická kalibrace pozic měničů. Tyto metody byly implementovány a otestovány na reálných datech pocházejících z prototypu USCT z Karlsruhe.

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