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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.
31

FEM model ultrazvukového senzoru hladiny oleje / Numerical model of ultrasonic oil level sensor

Chutný, Pavel January 2017 (has links)
This master’s thesis verifies physical principle of ultrasound in fluids by numerical model. At first, ultrasound study is ment. In second theoretic part, diferent kind of motor oils are described. Next, equations for numerical simulation are presented. In practical part, numerical model of level sensor is examined in well-knowed fluids (water, air). Results of laboratory measurement on topic of ultrasound velocity in oil dependent on temperature are aplicated on numerical model of sensor and optimalized.
32

Návrh algoritmu pro elektronickou fokusaci uzv sond. / Design of ultrasound probe focusation algorithm.

Maceška, Radek January 2011 (has links)
This thesis deals with electronic focusing of ultrasonic probes. There is theoretically described, what is the electronic focusing. Further, there are calculations that are used to achieve focusing. These calculations are then implemented into the algorithm that was developed in Matlab. The paper also contains the simulation conducted using the proposed algorithm and the GUI. These simulations are then compared with characteristics measured on a real ultrasound probe.
33

Zjišťování příznaků z obrazových dat / Feature extraction from image data

Uher, Václav January 2011 (has links)
Image processing is one area of signal analysis. This thesis is involved in feature extraction from image data and its implementation using Java programming language. The main contribution of this thesis lies in develop features extractors and their implementation in the program RapidMiner. The result is a robust tool for image analysis. The functionality of each operator is tested on mammogram images. A function model was developed for the removal of artifacts from the mammography images. The success rate of removal is comparable with other similar works. Furthermore, learning algorithms were compared on example detection of ventricle in ultrasound image.
34

Aktivní kontury pro segmentaci ultrazvukových dat / Ultrasound image registration based on active contours

Hesko, Branislav January 2015 (has links)
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.
35

Lokalizace vad svarů jeřábů / Locating welds defects on cranes.

Zíka, Luboš January 2012 (has links)
The diploma thesis deals with the problematics of weld defects of cranes localisation and check. The aim is to analyse non-destructive methods, monitor the occurence of defects and their form and also to suggest the procedure of correction. The work is divided into a theoretical and practical part. In the theoretical part, there is an analysis of individual methods of non-destructive testing that are used for weld check on a particular girder. There is also an analysis of welding technologies used when making a crane girder. The practical part deals with evaluation of weld defects using two methods of non-destructive testing. Furthermore, statistics of defects is realised. In conclusion, the statistics outcome is resumed and evaluated.
36

Vizualizace šíření ultrazvuku v lidském těle / Visualisation of Ultrasound Propagation in Human Body

Klepárník, Petr January 2014 (has links)
This work deals with the 2D and 3D visualization of simulation outputs from the k-Wave toolbox. This toolbox, designed to accurately model the propagation of ultrasound waves in the human body, usually generates immense amounts of output data (up to hundreds of GB). That is why new methods for both the visualization and the effective data representation are necessary to be developed to help users to easily understand the simulation results. This thesis elaborates on the data format, simulation outputs are stored in, with the use of the HDF5 library and looking for the best way to quickly read the simulation data. Finally, the thesis presents the design and the implementation of the console-based application for big simulation data pre-processing and the GUI-based application for interactive visualization of the pre-processed data. The most significant features of these applications are downsampling data, changing the format of storing, viewing 2D sections, planar and volumetric visualization and animation of the simulation process. The proposed implementation allows parts of the simulation domain to be visualised within tens of milliseconds even if the simulation domain comprises GBs of data - This significantly streamlines the work of scientists and clinicians in the field of HIFU.
37

Paralelizace ultrazvukových simulací pomocí akcelerátoru Intel Xeon Phi / Parallelisation of Ultrasound Simulations on Intel Xeon Phi Accelerator

Vrbenský, Andrej January 2015 (has links)
Nowadays, the simulation of ultrasound acoustic waves has a wide range of practical usage. As one of them we can name the simulation in realistic tissue media, which is successfully used in medicine. There are several software applications dedicated to perform such simulations. k-Wave is one of them. The computational difficulty of the simulation itself is very high, and this leaves a space to explore new speed-up methods. In this master's thesis, we proposed a way to speed-up the simulation based on parallelization using Intel Xeon Phi accelerator. The accelerator contains large amount of cores and an extra-wide vector unit, and therefore, is ideal for purpose of parallelization and vectorization. The implementation is using OpenMP version 4.0, which brings some new options such as explicit vectorization. Results were measured during extensive experiments.
38

Návrh systému pro hlášení úniku plynu pomocí ultrazvukového mikrofonu / Design of system for indication of gas leakage by ultrasonic microphone

Bohuš, Michal January 2017 (has links)
The aim of this project is detection of gass leak based on the ultrasound sensing. Work introduces ultrasound, mechanism of its propagation and attenuation. From all of the available microphones, the piezoelectric microphone was chosen. Project continues with description of the device, which can be capable of detection of the ultrasound leakage in dangerous, explosive environment. This type of device must meet requirements of SIL 2 standard and ATEX directive for zone 2. Project discusses LNA (Low Noise Amplifier), filters and detection circuits design. The device is modular what means that each module can be freely replaced. The role of these modules is to convert analog signal to digital form suitable for microcontroller HERCULES TSM57012.
39

Návrh algoritmu pro anonymizaci ultrazvukových dat na úrovni snímku / Design of algorithm for anonymization of ultrasound data

Bugnerová, Pavla January 2017 (has links)
This master’s thesis is focused on anonymization of ultrasound data in DICOM format. Haar wavelet belonging to Daubechies wavelet family is used to detect text areas in the image. Extraction of the text from the image is done using a free tool - tesseract OCR Engine. Finally, detected text is compared to sensitive data from DICOM metadata using Levenshtein - edit distance algorithm.
40

Cévní zásobení a prokrvení ženské uretry ve vztahu k poruchám kontinence : stanovení vyšetřovacích metod a jejich praktické použití / Vascularity of Female Urethra in Correlation to Urinary Incontinence : Diagnostic Algorithms and Its Clinical Implications

Švabík, Kamil January 2011 (has links)
Introduction: Intrinsic and extrinsic urethral factors play a significant role in urinary continence mechanism in women. Urethral wall structure including inervation, perfusion of submucosal layer etc. is not clinically assessed despite its important role in urethral closure function. The association of incontinence and pelvic floor reconstructive surgery is well known. Every postoperative healing process is associated with factors of ischemia and neovascularisation. According those facts we would expect that the healing and scaring should involve intrinsic urethral mechanism. After reconstructive surgery Implants further increase scaring process. Methods: In our study we included patients with anterior compartment defect. We randomized patients into three interventional arms according the surgical approach and use of implants. Before and 3-5 month after the surgery we performed urodynamic studies and pelvic floor ultrasound examination, including Doppler for urethral perfusion assessment. Another early ultrasound scan was added forth day after surgery. We correlated ultrasound and urodynamic parameters. Results: We randomized 87 patients. We couldn't find any correlation between the morphologic changes and severity of incontinence. Methods for urethral perfusion assessment showed high inaccuracy...

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