|
|
Segmentation of amyloid plaques in brains of trangenic rats based on microCT image data
Kačníková, Diana ; Kolář, Radim (referee) ; Chmelík, Jiří (advisor)
The presence of amyloid plaques in the hippocampus highlights the incidence of Alzheimer’s disease. Manual segmentation of amyloid plaques is very time consuming and increases the time that can be used to monitor the distribution of amyloid plaques. Distribution carries significant information about disease progression and the impact of potential therapy. The automatic or semi-automatic segmentation method can lead to significant savings in the time which are required when the disease has rapid progression. The description of amyloid plaques and the computed tomography are included in this work. In this diploma thesis are three implemented algorithms, two of them are based on published articles and one’s own methodological solution. The conclusion of the thesis is a quantitative evaluation of the accuracy of implemented segmentation procedures.
|
|
|
Software tool for education of the computed tomography
Doležalová, Anna ; Králík, Martin (referee) ; Mézl, Martin (advisor)
This semestral thesis is focusing on the process of displaying X-ray scanning and it’s simulation. There is described X-ray radiation and it’s possible interactions and changes. It’s also focused on the origin and detection of this radiation. In the practical part of the thesis, there is simulated the origin and attenuation of spectrum while comming through material. Then simulation software is created using MATLAB program. The simulation software allows to simulate basic processes of classical systems: X-ray tube, the interaction of radiation with the patient and subsequent detection. After selecting parametrs of simulation, the effects of the selected parametrs and X-ray spectrum will be displayed. The thesis also describes and subsequently simulates how image reconstruction of computed tomography works.
|
|
|
Development and use of non-destructive testing methods from the point of view of forensic engineering
Bílek, Petr ; Vala, Jiří (referee) ; Vodička, Jan (referee) ; Hobst, Leonard (advisor)
Concretes reinforced by, using distributed steel reinforcements (fibres) are known as fibre-concrete. In case of disturbances or accidents of concrete structures reinforced with wires, it is necessary to carefully examine the actual implementation of dispersed reinforcement. Fibre concretes belong to modern building materials whose possible applications have not been fully utilized so far. Have been mainly used for floor structures loaded with factory halls and warehouses. Recently, thanks to well-known physical and mechanical properties of fibre-concrete, there were numerous attempts of designers, and namely investors, to utilize this kind of materials for support structures either. Favorable properties of wire-concrete can be utilized if there is a necessity to increase the resistance of concrete to stresses exceeding its strength, cyclic stress or impact stress. Daily practice shows to prove that the applications of fibre-concrete in such structures lead to the economic success. Necessary condition for successful application of steel fiber reinforced concrete in constructions however consists in its uniform dispersion, a homogeneous distribution of the wires throughout the volume of the structure. In case of inappropriate processing and deposition of the mixture during the manufacturing process fiber-concrete structures, the fibers are often unevenly distributed. Wires itself represent unfavourably shaped mixture components and they are extremely deteriorating its workability. A grouping of wires may be encountered as well, which reduces the overall homogeneity and the quality of steel fiber-concrete structures. If the homogeneity of fibre-concrete is not kept, the material possess different properties in various parts of the structure (for example, tensile strength), which can lead to defects in the structure (generation and development of cracks). The relevant lower reliability of the structure which is caused by unequal distribution of fibres (wires) in concrete volume can lead to damage of the property as well as the safety and the human lives can be jeopardized. Hence it is necessary to secure the effective control of the fibre-concrete homogeneity in ready support fibre-concrete structures. Contemporary homogeneity control is still ongoing on fresh blends, but if the fibre-concrete hardened and is a part of the construction, no known reliable methods are currently in available to test the homogeneity of the fibre-concrete on the structure without its destruction. The methods developed to control the concentration of wires in wire-concrete structures are based mostly on magnetic or electromagnetic properties of wires. The thesis deals with the development of the magnetic method in situ using permanent magnets for monitoring the distribution of fibers in hardened steel fiber-concrete structures. The test principle is based on measurements of the changes in magnetic field strength of permanent magnets which are induced by a change in wire distribution in steel fibre-concrete structure. Test is characterized as a so called local- failure- test using a small diameter core drill. In this sense it is a semi-destructive method.
|
|
|
Quality control of injection molded plastics using X-ray computer tomography
Figar, Erik ; Šrámek, Jan (referee) ; Jankových, Róbert (advisor)
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.
|
|
|
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.
|
|
|
X-ray Defectoscopy
Velím, Michael ; Ondřej, Šimeček (referee) ; Starý, Jiří (advisor)
This diploma thesis deals with a defect detection with X-rays in the manufacturing procedure in the electrotechnical field. The work summarises the knowledge about technical possibilities of an X-ray device Cougar of YXlon company. Part of the work is focusing on scanning in 2D, 3D visualization and automatic analysis. The thesis describes inspection methods of a connector connection, the quality of a soldered joint and an encapsulated product.
|
|
|
Affine registration of native and contrast-enhanced CT brain images
Chmelík, Jiří ; Mézl, Martin (referee) ; Walek, Petr (advisor)
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.
|
|
|
Method for Extending the Field of View for X-ray Computed Tomography with Submicron Resolution
Zemek, Marek ; Chmelík, Jiří (referee) ; Mézl, Martin (advisor)
Výpočetní tomografie je nástroj pro nedestruktivní inspekci vzorků, který je běžně používán v mnoha oblastech průmyslu a výzkumu. Některé tomografické přístroje umožňují snímání obrazů s prostorovým rozlišením pod jeden mikrometr. Zorné pole takovýchto přístrojů bývá malé, v rozsahu jednotek milimetrů či méně. Tím jsou omezeny rozměry vzorků, což je značně limitující. Toto omezení lze překonat pomocí různých technik pro rozšíření zorného pole. Jedna takováto dříve publikovaná metoda byla v této práci upravena a implementována pro přístroj Rigaku Nano3DX. Tato technika téměř zdvojnásobuje zorné pole přístroje bez nutnosti většího detektoru. Implementovaný přístup byl testován pomocí umělých i skutečných dat, a jeho účinnost byla zhodnocena subjektivně i objektivně, pomocí vizuální kontroly a metrik kvality obrazu. Hodnocení je převážně založeno na srovnání obrazů rekonstruovaných pomocí této metody s obrazy získanými pomocí většího detektoru. Implementovaná technika rozšíření zorného pole poskytuje věrné rekonstrukce vzorku, srovnatelné se zmíněnými protějšky.
|
|
|
Laboratory exercise for RTG imaging systems
Kuchař, Otakar ; Macíček, Ondřej (referee) ; Mézl, Martin (advisor)
The aim of this Bachelor thesis is to study the X-ray and computed tomography. The theoretical section explains the basic physical principles, elementary particle, atom and ionizing. The following parts of the thesis deal with topics from the origin and various types of X-ray, to interaction of X-ray with tissue and X-ray detection. For computed tomography the thesis also explains data collection, the reconstruction of image using simple back projection, filtered back projection and algebraic reconstruction. In the practical part are analysed several measurements which were taken in the X-ray chamber designed for educational purposes by Leybold. The topics solve the attenuation of X-rays depending on the type and thickness of the material and the spectrum of the X-ray radiation. In the field of computerized tomography solve tasks as the change of contrast, parameters of acquisition and methods for reconstruction. The work includes prepared sample solutions to a laboratory experiments.
|
|
|
Development of finite element model of human vocal tract and space around the head based on data from computer tomography
Švarc, Martin ; Pellant, Karel (referee) ; Švancara, Pavel (advisor)
This bachelor´s thesis deals with creating a computational model for acoustic wave propagation in vocal tract and the area near the head. The main objective of this work is to map the three-dimensional model of the human head as an additional acoustic environment for more accurate measurement of the human voice on the basis of data from computed tomography, the study of function of the vocal cords, biomechanics of the human voice and an overview of medical imaging techniques suitable for the display of biomechanical models. The grid for finite element method (FEM) will be created from solid geometry of the vocal tract (from the vocal cords to the lips) and the acoustic space near the human head. The grid will be created in order to obtain new knowledge about the different locations of a human head with microphone.
|
guest ::
