National Repository of Grey Literature 77 records found  previous11 - 20nextend  jump to record: Search took 0.00 seconds. 
Image analysis in heat transfer.
Hnízdil, Milan ; Martišek, Dalibor (referee) ; Horský, Jaroslav (advisor)
Cílem této práce je porovnat vysoko tlaké vodní trysky a vysvětlit čtenáři použité metody. Matematické metody použité v programu jsou také uvedeny v této práci.
Calibration and interpretation of images measured by LEEM
Endstrasser, Zdeněk ; Novák, Jiří (referee) ; Čechal, Jan (advisor)
This thesis deals with the software development to calibration and interpretation of image data measured by a LEEM device. As the imaging technique is uniquely suited for in-situ studies of surface dynamical processes, the attention is mainly paid to methods enabling the evaluation of measurement time series. The phase correlation method based on Fourier transform of images is proposed to temperature shift correction between consecutive frames. The thesis describes the methods of additive and impulse noise filtering, image visualization, the filtration of secondary electrons and the determination of I-V curves from measured image data. Implemented methods are described not only in terms of their mathematical origin, but also with emphasis on the revealing of critical aspects associated with their use. The thesis also focuses on the application of the created algorithm to image data capturing the spatial and temporal evolution of 4,4’-biphenyl-dicarboxylic acid surface phases induced by sample annealing. Based on these evaluations, a suitable procedure is then determined to perform accurate detection and compensation of temperature shift said.
Multiple sclerosis detection
Kopuletý, Michal ; Mangová, Marie (referee) ; Uher, Václav (advisor)
This thesis is focused on detecting multiple sclerosis lesions from magnetic resonance images. Correctly retrieved lesions are very important for medical diagnosis. Detection of lesions using machine learning techniques is quite challenging because of large variability in size, shape and position of lesions in the brain. In the practical part is designed base software, which after completion will classify pixels, so that is possible to find lesions of multiple sclerosis. For classification will be used Support vector machine. Theoretical part describes multiple sclerosis, basic operations performed with biomedical images and data classification.
Effect of curing conditions on shrinkage of alkali activated systems
Pragerová, Barbora ; Kotrla, Jan (referee) ; Kalina, Lukáš (advisor)
This bachelor thesis deals with the determination of optimal curing conditions of alkali-activated systems in order to reduce shrinkage. Hardened alkali-activated blast-furnace slag pastes activated by sodium silicate were tested in the empirical part. Six varieties of curing conditions were compared. Immediately after demolding process, three sets of samples were stored in air, water and plastic film. Another three sets were first placed in water for 14 days, then removed and two of them impregnate with lithium silicate and acrylate-based coatings. The formation and the number of cracks were monitored by an optical method. The percentage of cracks was evaluated by the ImageJ program. The highest number of cracks was formed after 7 days of curing, given the samples placed in the open air. Some them were filled later. Samples placed in the open air after being submerged in water for 14 days showed a rapid increase of cracks as well, but the percentage of cracks was reduced to 50 %. Treating agents reduced the development of cracks but have not stopped their formation. After 36 days of curing, the results of these types of curing conditions were comparable. Only the samples wrapped in plastic foil showed a minimum number of cracks and no cracks were observed if the samples were submerged in water. The lowest levels of shrinkage were reached with the samples placed in water, and with the ones wrapped in plastic foil. Samples stored in water for the first 14 days showed the identical tendency of high-level shrinkage, as did the ones placed in the open air.
Brain Tumor Detection and Segmentation in Multisequence MRI
Dvořák, Pavel ; Přibil, Jiří (referee) ; Šprláková-Puková,, Andrea (referee) ; Smékal, Zdeněk (advisor)
Tato práce se zabývá detekcí a segmentací mozkového nádoru v multisekvenčních MR obrazech se zaměřením na gliomy vysokého a nízkého stupně malignity. Jsou zde pro tento účel navrženy tři metody. První metoda se zabývá detekcí prezence částí mozkového nádoru v axiálních a koronárních řezech. Jedná se o algoritmus založený na analýze symetrie při různých rozlišeních obrazu, který byl otestován na T1, T2, T1C a FLAIR obrazech. Druhá metoda se zabývá extrakcí oblasti celého mozkového nádoru, zahrnující oblast jádra tumoru a edému, ve FLAIR a T2 obrazech. Metoda je schopna extrahovat mozkový nádor z 2D i 3D obrazů. Je zde opět využita analýza symetrie, která je následována automatickým stanovením intenzitního prahu z nejvíce asymetrických částí. Třetí metoda je založena na predikci lokální struktury a je schopna segmentovat celou oblast nádoru, jeho jádro i jeho aktivní část. Metoda využívá faktu, že většina lékařských obrazů vykazuje vysokou podobnost intenzit sousedních pixelů a silnou korelaci mezi intenzitami v různých obrazových modalitách. Jedním ze způsobů, jak s touto korelací pracovat a používat ji, je využití lokálních obrazových polí. Podobná korelace existuje také mezi sousedními pixely v anotaci obrazu. Tento příznak byl využit v predikci lokální struktury při lokální anotaci polí. Jako klasifikační algoritmus je v této metodě použita konvoluční neuronová síť vzhledem k její známe schopnosti zacházet s korelací mezi příznaky. Všechny tři metody byly otestovány na veřejné databázi 254 multisekvenčních MR obrazech a byla dosáhnuta přesnost srovnatelná s nejmodernějšími metodami v mnohem kratším výpočetním čase (v řádu sekund při použitý CPU), což poskytuje možnost manuálních úprav při interaktivní segmetaci.
Blood vessel tree segmentation of the mouse liver in CT data
Smékalová, Veronika ; Odstrčilík, Jan (referee) ; Kolář, Radim (advisor)
The methodology of visualization of soft tissue is in biology and medicine a topic for many years. During this period there were approving many techniques how to achieve accurate and authentic image of the researched object or structure. X-ray computed tomography is very helpful to get this goal but is necessary to improve contrasting techniques as well as the techniques of image post-processing. This thesis deals with imaging soft tissue. Specifically, it focuses on mouse liver contrasting with the artificial resin Microfil. Thesis also describes image processing technique (thresholding and region growing) for the data of the measurement with the goal of the visualization of the sample in 3D.
Batch generation of graphical presentations
Semerák, Jakub ; Szőke, Igor (referee) ; Beran, Vítězslav (advisor)
This thesis describes design and implementation of system that allows batch generation of graphical presentations. The system also includes modules for image quality evaluation using no-reference blur metric and salient object detection. Selected methods for evaluation of image quality are described in detail and implemented in corresponding chapters, including proposed modifications and changes. Blur detection is based on wavelet transform, and salient object detection is achieved by investigating image contrast. Capabilities of these modules are evaluated on suitable image datasets.
System for preventing unauthorised persons from entering platform areas
Jílek, Michal ; Říha, Kamil (referee) ; Přinosil, Jiří (advisor)
The work deals with the design of a non-existent security system to secure the station from unauthorized persons, which will increase the level and quality of travel for passengers. The system uses computer vision and software developed in C ++ with the OpenCV library. The practical part describes the development of the ticket detector, comparison with the model and validation of the ticket using OCR.
Evaluation of dental pulp treatment based on the X-ray micro computed tomography
Břínek, Adam ; Jiřík, Radovan (referee) ; Zikmund, Tomáš (advisor)
This work deals with processing and analysis of micro-CT images of dental-canals filled by~two materials (AH-plus and NaMPC). For that reason, six dog-teeth were scanned in the X-Ray Micro CT Research Lab. The main aim was to produce an algorithm (in Matlab) that evaluates the quality of filling of dental canals (quality of filling materials). The algorithm performs the segmentation of dental canals and calculates their borders. Also, the algorithm measures the percentage contacts of filling materials with dental walls. Moreover, the algorithm provides masks of dental canals according to requirements of the commercial program VG Studio, that evaluates the porosity of filling materials. The results of percentage contacts and porosities show on not-remarkable differences of tested filling materials.
Application of mathematical methods for object detection in ultrasound B-image
Ruttner, Michal ; Jiřík, Radovan (referee) ; Sedlář, Martin (advisor)
This work deals with the detection of objects in ultrasound B-image. First we will become familiar with the ultrasound device and its functions.We will demonstrate various kinds of imaging techniques used in ultrasound diagnostic imaging. Further we will be concerned with medical image processing. We will describe the functions of some edge detectors based on the first derivation, detectors based on the second derivation, detectors based on approximation of parametric model and detectors of borders or lines. Otherwise we will find out how to do preprocessing, Some of these methods we will try on different images for sharpening of image and enhacment of contoure. Using the program created in MATLAB©, we will use process imaging on internal carotid images. In conclusion we will evaluate the results.

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