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Filtering methods for MR images processing
Pláněk, Jiří ; Smékal, Zdeněk (referee) ; Gescheidtová, Eva (advisor)
This master´s thesis deals with wavelet transformation and its signal and image noise reduction application method. Significant parameters problems as a wavelet type, a threshold technique selection, a threshold level and a level analysis selection for successful signal and noise image filtering are described. A relation between wavelet transformation and digital bank filter is used by anti-noise and sub-bandwidth filtration. A part of the master´s thesis is focused on nuclear magnetic resonation, where jaw-joint image is processed. Jaw joint image noise reduction filtration methods are used in experimental part of the master´s thesis. Consequently, filtration methods improve a jaw joint image quality, which helps a doctor with patient health state condition. Different types of wavelets were tested and in different application methods order. Filtration methods results were visually compared; therefore any conclusion comparison has subjective matter. Accordingly, only doctor is able to resolve which filtration method is convenient to use to determine patient health state.
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Measurement of spruce needles by magnetic resonance imaging
Slivka, Ján ; Gescheidtová, Eva (referee) ; Bartušek, Karel (advisor)
The aim of this bachelor thesis is measuring of parameters of spruce needles from their 2D visual representation. To obtain the image, the magnetic resonance was used, specifically spin echo sequence. Further work is focused on digital image processing in order to obtain the necessary image information. The algorithm of linear mask operator was applied for reducing of noise and segmentation of image by thresholding was performed. Geometric properties of examined objects were obtained by integrated functions in MATLAB.
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MR image data processing in study of tissue cultures
Bidman, Petr ; Šmirg, Ondřej (referee) ; Gescheidtová, Eva (advisor)
Techniques based on principle of nuclear magnetic resonance (NMR) belong to the most modern methods for studying physical, chemical and biological properties of materials [1]. Their universality predestinates them for application in a wide range of scientific disciplines, e.g. in medicine to study properties of tissues. Advantages of techniques utilizing principle of NMR consist in their noninvasiveness and thoughtfulness to human health or studied material. In addition, no undesirable effects of magnetic force field have been so far proved by research. Objectives of this Diploma Thesis are evaluation of MR images of tissue cultures and determination of protons amount included in them. Theoretic part of the Thesis is devoted to the bases of NMR and provides basic overview of MR methods. The spin echo method (SE) is described in more details, including the process of assessment of technique’s parameters, e.g. general magnetization. Practical part of Diploma Thesis is focused on determination of integral of image intensity of clusters of early somatic embryos. Intensity integrals characterizing number of protons in growing cluster were calculated from MR images of spruce embryos contaminated by lead. The intensity of an image weighted by spin density is proportionate to the number of proton nuclei in the chosen slice. The Thesis describes further evaluation of relaxation time T2 from MR images weighted by spin density. Following part is dealing with determination of diffusion from MR images with application of compensation methods, three-measurement arrangement and presentation of obtained results. Images were processed by use of MATLAB and MAREVISI programs.
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Propoasl of a laboratory workplace for verifying the NMR principle
Kropáč, Ondřej ; Bartušek, Karel (referee) ; Gescheidtová, Eva (advisor)
This project deals with the design of a laboratory workplace for verifying the basic principles of nuclear magnetic resonance. In the theoretical part of the project a basic knowledge of nuclear magnetic resonance are summarized, and the process of evaluation the results obtained from NMR signal is described. The proposed part of work is aimed at a design of a NMR spectrometer block diagram and a proposal of a resonant circuit and NMR probes. In the practical part the technologic process of the probes production and their settings are specified. The results of the designed probes comparison are in the last, measuring, part.
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Segmentation Methods in Biomedical Image Processing
Mikulka, Jan ; Přibil, Jiří (referee) ; Dostál, Otto (referee) ; Gescheidtová, Eva (advisor)
The PhD thesis deals with modern methods of image processing, especially image segmentation, classification and evaluation of parameters. It is focused primarily on processing medical images of soft tissues obtained by magnetic resonance tomography (MR) and microscopic images of tissues. It is easy to describe edges of the sought objects using of segmented images. The edges found can be useful for further processing of monitored object such as calculating the perimeter, surface and volume evaluation or even three-dimensional shape reconstruction. The proposed solutions can be used for the classification of healthy/unhealthy tissues in MR or other imaging. Application examples of the proposed segmentation methods are shown in this thesis. Research in the area of image segmentation is focused on methods based on solving partial differential equations. This is a modern method for image processing, often called the active contour method. It is of great advantage in the segmentation of real images degraded by noise with fuzzy edges and transitions between objects. The results of the thesis are methods proposed for automatic image segmentation and classification.
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Optimization of MR acquisition parameters for the measurement of small objects
Pecháček, Libor ; Přinosil, Jiří (referee) ; Gescheidtová, Eva (advisor)
The subject of my thesis is a design of the methods optimizing, the acquisition of MR signals when small objects measure. The thesis is divided into several parts in order to give a deeper knowledge of the problem. The first part focuses on the theory associated with NMR (Nuclear Magnetic Resonance) and SNR (signal-to-noise ratio). The practical verification of the theory follows. The conclusion of this work is focused on MR images filtering by use of wavelet transform to suppress a noise in the image. The method optimization of MR acquisition parameters for the measurement of small objects is then distributed to the entire work.
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Diffussion measurement by NMR
Vanko, Filip ; Gescheidtová, Eva (referee) ; Bartušek, Karel (advisor)
In Bachelor thesis is described the principle of MRI, the physical foundations of the phenomenon of magnetic resonance imaging, quantum and macroscopic model. Followed by a description of the mechanisms of relaxation of magnetic resonance phenomenon. In the following sections describes the basis of diffusion, each sequence for measuring diffusion NMR methods and the method of three measurements, which was used in experimental measurements. Last chapter deals with the practical. The results of measurements are evaluated in conclusion.
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Designing an automated workplace for charge and high-impedance measurement
Nemček, Jakub ; Bartušek, Karel (referee) ; Gescheidtová, Eva (advisor)
This barchelor thesis is about Desig an automated workplace forchargeable and high-impedant measurements. This automated workplace is realized by tubular aspiration capacitor, which is connected via differential converter U/I to data acquisition switch unit HP 34970A. The data acquisition switch unit HP 34970A is also connected by serial line RS-232 to Computer (PC), on which the directed program Agilent VEE Pro 7.0 is installed. To the right connection data acquisition switch unit HP 34970A and PC is necessary to set the same parameters on data acquisition switch unit HP 34970A, such in I/O config and also in Instrument manager too. In Instrument manager is requisite to set Plug und Play driver for data acquisition switch unit HP 34970A. The programing in Agilent VEE Pro 7.0 is based on object oriented programming. To start the program press the button “START“ and automatic measuring of concentration air ionts, will start the process (the trend is marked to the graph). The program is indicated if the ventilator blows an air in the aspiration capacitor and draws the trend of voltage on this ventilator to the graph. To stop the program press the buton “STOP“. Measured data are exported to program Excel. For the export Excel has to be running before the process. The function is verifing by measuring of background negativ a positiv ionts, by influence of position the source of ionts behind the aspiration capacitor and by influence of materials (metal plate, paper carton, wood, conductive paint) to the concentration of negativ ionts.
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Filtering methods in NMR measurements
Ryšavý, Ladislav ; Rajmic, Pavel (referee) ; Gescheidtová, Eva (advisor)
Bachelor's thesis deals with the wavelet transform and its use in processing and removing noise from images acquired by nuclear magnetic resonance. In the theoretical part of work is briefly described the principle of nuclear magnetic resonance, the wavelet transform is described, the selection of appropriate wavelets for filtering, two-dimensional wavelet transform for the processing of image data and appropriate tresholding techniques. The experimental part is focused on the filtration of magnetic fields and map images jaw joint as maps fields. They are filtering the results using different types of waves. It is shown through the evaluation of filtration ratio signal / noise and the steepness of the signal in the image.
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