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Ultrasound image processing
Pokorný, Vojtěch ; Harabiš, Vratislav (referee) ; Mézl, Martin (advisor)
Ultrasound is an important imaging modality used in medicine. This bachelor’s thesis includes theory regarding physical characteristics of ultrasonic waves, a brief overview of the historical development of ultrasound as an imaging modality in medicine, biophysics of spreading and biological effects of ultrasound waves on tissues and types of display final images. Next part of the thesis describes diagnostic ultrasound device, including the most common used types of ultrasound probes. This part is followed by description of animal Vevo 2100 ultrasound system from which the acquired data are processed further. Processing includes the loading, display and for DICOM files saving too. At various file formats DICOM standard comparison is done. The last chapter deals with the filtration of characteristic noise for ultrasound images called speckle.
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Speckle noise suppression
Kuchař, Otakar ; Hesko, Branislav (referee) ; Mézl, Martin (advisor)
Master thesis deals with the study of ultrasound. The first part of this work is devoted to basic physical principles, imaging modes, ultrasound probes, biological effects and the last part is associated with the artifact associated with ultrasound waves. In the next part the specific noise called speckle noise is detaily discussed. The description includes both a mathematical and a statistical view. Several methods are described to eliminate this noise. In the practical part the described methods are realized and compared based on objective and subjective evaluation.
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Specle analysis for optical coherence tomography image segmentation
Gallo, Vladimír ; Kolář, Radim (referee) ; Štohanzlová, Petra (advisor)
This paper presents basic principles of optical coherence tomography, review of applications and basic categorization of these systems. Paper also deals with the typical properties of images from optical coherence tomography, especially speckle pattern. This paper also provides an overview of the origin of speckle noise and utilization of its dependence on microstructure of probed tissue for image classification based on textural analysis. Experimental part of this paper consists of phantom preparation, data acquisition by OCT system, implementation of speckle analysis in MATLAB and of testing of its functionality on standard textural dataset and also on acquired image phantom data. Speckle analysis is used for phantom image data segmentation.
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Image processing of data from the ultrasound system GE VingMed System Five
Pokorný, Pavel ; Mézl, Martin (referee) ; Harabiš, Vratislav (advisor)
The master thesis is focused on the principle of ultrasonographs and their modes, and ways of denoising data obtained by ultrasonographs. This project will also concentrate on removing the speckle noise, because the speckle noise has the largest share of the noise in the measured data in ultrasonographs. The other main objective was to describe advanced methods of filtration, especially the modifications of the median filter, such as the modified hybrid median filter and modification of the anisotropic diffusion, namely generalizing Perona-Malik anisotropic diffusion using restricted dissimilarity functions. These two filters were tested on images with artificial noise and on data captured using the ultrasound system GE VingMed System FiVe. Also, the program for filtering and display filtered ultrasound data captured by GE VingMed System FiVe is described.
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Speckle noise suppression methods in ultrasound images
Tvarůžek, Marek ; Harabiš, Vratislav (referee) ; Mézl, Martin (advisor)
This diploma thesis deals with the methods of despeckling in ultrasound images. Ultrasound imaging and related artifacts are described in more details. Ultrasound imaging has its pros and cons, where speckle noise is a disadvantage to be solved. Models of origin of this specific noise are referred too. Practical part of this thesis aims on filtering speckled images by basic and advanced filtering methods as are linear filtering, median filtering, application of Frost filter, QGDCT, geometric filtering, anisotropic diffusion filtering and filtering based on wavelet transformation. Results are compared on the basis of objective criteria.
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Ultrasound image registration based on active contours
Hesko, Branislav ; Jakubíček, Roman (referee) ; Harabiš, Vratislav (advisor)
This diploma thesis aims to implement an active contour method for ultrasound image segmentation. Properties of ultrasound images, basic segmentation approaches and a~principle of choosen active contour methods are described within theoretical part. Two different groups of active contour methods exists, methods with use of gradient and without use of gradient as image feature. For comparision, one method of each group is implemented in practical part and subsequently, segmentation efficiency and properties of methods are compared in evaluation part.
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Analysis of dynamic parameters of laser vibrometers
Pavloň, Martin ; Vágner, Martin (referee) ; Havránek, Zdeněk (advisor)
This diploma thesis deals with the theoretical description of interference methods used to measure vibrations, examines main parasitic effects and analyses its contribution to achievable the resolution. In the practical part, it uses several measurements to verify the effects of the level of reflected beam, stand-off distance and speckle noise. It also proposes a practical experiment for measuring dynamic parameters and signal-noise ratio. Results show that, the noise is exponentially dependent on the level of the reflected beam. The visible maximum of the vibrometer proved to be critical in terms of time stability of the measured signal level in two of the three measurements. Results of the dynamic measurement show that, the measured deviations were not degraded or significantly disturbed by the noise signal. From the measurement of the speckle noise, it emerged that the lowest level of noise is achieved with smooth and highly reflective materials.
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Speckle noise suppression
Kuchař, Otakar ; Hesko, Branislav (referee) ; Mézl, Martin (advisor)
Master thesis deals with the study of ultrasound. The first part of this work is devoted to basic physical principles, imaging modes, ultrasound probes, biological effects and the last part is associated with the artifact associated with ultrasound waves. In the next part the specific noise called speckle noise is detaily discussed. The description includes both a mathematical and a statistical view. Several methods are described to eliminate this noise. In the practical part the described methods are realized and compared based on objective and subjective evaluation.
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|
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Analysis of dynamic parameters of laser vibrometers
Pavloň, Martin ; Vágner, Martin (referee) ; Havránek, Zdeněk (advisor)
This diploma thesis deals with the theoretical description of interference methods used to measure vibrations, examines main parasitic effects and analyses its contribution to achievable the resolution. In the practical part, it uses several measurements to verify the effects of the level of reflected beam, stand-off distance and speckle noise. It also proposes a practical experiment for measuring dynamic parameters and signal-noise ratio. Results show that, the noise is exponentially dependent on the level of the reflected beam. The visible maximum of the vibrometer proved to be critical in terms of time stability of the measured signal level in two of the three measurements. Results of the dynamic measurement show that, the measured deviations were not degraded or significantly disturbed by the noise signal. From the measurement of the speckle noise, it emerged that the lowest level of noise is achieved with smooth and highly reflective materials.
|
|
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Ultrasound image processing
Pokorný, Vojtěch ; Harabiš, Vratislav (referee) ; Mézl, Martin (advisor)
Ultrasound is an important imaging modality used in medicine. This bachelor’s thesis includes theory regarding physical characteristics of ultrasonic waves, a brief overview of the historical development of ultrasound as an imaging modality in medicine, biophysics of spreading and biological effects of ultrasound waves on tissues and types of display final images. Next part of the thesis describes diagnostic ultrasound device, including the most common used types of ultrasound probes. This part is followed by description of animal Vevo 2100 ultrasound system from which the acquired data are processed further. Processing includes the loading, display and for DICOM files saving too. At various file formats DICOM standard comparison is done. The last chapter deals with the filtration of characteristic noise for ultrasound images called speckle.
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