|
|
Analysis of Colour Retinal Images Aimed at Segmentation of Vessel Structures
Odstrčilík, Jan ; Jiřík, Radovan (referee) ; Jan, Jiří (advisor)
Segmentation of vessel structure is an important phase in analysis of retinal images. The resulting vessel system description may be important for diagnostic of many eye and cardiovascular diseases. A method for automatic segmentation of the vessel structure in colour retinal images is presented in the thesis. The method utilises 2D matched filtering to detect presence of short linear vessel sections of a particular thickness and orientation. The approach correlates the local image areas with a 2D masks based on a typical brightness profile perpendicular to vessels of a particular width. Three different approximated profiles are used and corresponding matched filters are designed for: thin, medium and thick vessels. The evaluation of typical vessel profiles and filter design are described in chapter 3 and chapter 4. The parametric images obtained by convolution of the image with the masks are then thresholded in order to obtain binary representation of vessel structure. The three binary representations are consequently combined to provide the best available rough vessel map, which is finalised by complementing the obviously missing vessel sections and cleaning the disconnected fractional artefacts. The thresholding algorithm and final steps of processing are mentioned in chapter 5 and chapter 6. The method has been implemented by computer and the program for automatic vessel segmentation has been developed using database of real retinal images. The efficiency of the method has been finally evaluated on images from the standard database DRIVE.
|
|
|
Modelling of the ultrasound intensity in contrast imaging
Lacko, Jiří ; Jiřík, Radovan (referee) ; Kolář, Radim (advisor)
There are several mathematical compartment models developed in this thesis. Their purpose is to compute the concentration of ultrasonographic contrast agents in different compartments (simple two-compartment model, compartment model of liver and chain of N compartments). Based on these concentraitions the change of image brightness is set and the indicator dilution Curve is computed. Each of models is influenced by bolus of contrast agents, blood flow and decay of injected contrast agents.
|
|
|
Segmentation in the color fundus imges
Malínský, Miloš ; Jiřík, Radovan (referee) ; Kolář, Radim (advisor)
Optic nerve head and macula are important structures in fundus images. Detection and measurement plays crucial role in several diagnosis methods of optic disease. This work is focused on the detection of the central point of macula and optic nerve head, where the inner border is detected too. There are many methods for extracting this structure in retinal images. Due to the unique properties of each acquisition technique, a single generally acknowledged detection algorithm does not exist. The whole detection process is described from preprocessing through segmentation towards postprocessing. Presented methods are based on the combination of correlation techniques, Hough transform, active contours and morphological operations. The detected contours of the optic nerve head are evaluated and quantitatively compared with the contour drawn by experienced ophthalmologist. The master thesis contains quantity of images that help to describe detection methods.
|
|
|
Ultrasound attenuation measurement
Feller, Michal ; Kolář, Radim (referee) ; Jiřík, Radovan (advisor)
This diploma thesis deals with ultrasound attenuation measurement methods. Variety of methods are developed and tested . Castor oil was used as reference material. Different kinds of ultrasound transducers, hydrophone and ultrasound scanner GE Vingmed SystemFive were used for measurement. Data was processed by scripts developed in matlab.
|
|
|
Measurement of ultrasound speed using transmission tomography
Pop, Tomáš ; Kolář, Radim (referee) ; Jiřík, Radovan (advisor)
The study deals with the image reconstructions using the ultrasound propagation speed measuring and it extends the project of the ultrasound transmission tomography organised in cooperation with the research centre Forschungszentrum Karlsruhe (Germany). There were data processed which had been gained with the 3D ultrasound transmission tomography system (3D USCT). The ultrasound propagation speed was measured using the detection of ultrasound ray travelling time from a transmitter to a receiver. There were three new algorithms developed for the detection of an ultrasound impulse and the software generating suitable testing data. The developed algorithms were consequently tried with these data and, then, included into the existing software. All software was developed within the Matlab programming environment.
|
|
| |
|
|
SMV-2013-07: Development and validation of a body of methods for imaging and analysis of an animal model of schizophrenia by 9.4-Tesla magnetic resonance, and analysis of a sample provided
Starčuk jr., Zenon ; Dražanová, Eva ; Jiřík, Radovan ; Rychnovský, Jan ; Starčuková, Jana ; Kořínek, Radim
A contract-based research with a specified mouse model of schizophrenia was carried out, examining the possibility of imaging relevant parameters of the structure and function of organs specified by the client. The options were assessed with respect to client's needs, suitable imaging methodology was identified and developed, animal experiment protocols were prepared and validated, and the proposed methodology was applied to a series of 60 animals according to valid animal use protocols. Original and statistically evaluated data were provided to the client.
|
|
|
The Synthesis, Surface Modification and Stability of SPIO Nanoparticles for MRI Application
Kovář, D. ; Fohlerová, Z. ; Malá, A. ; Jiřík, Radovan ; Starčuk jr., Zenon ; Kalina, M. ; Skládal, P.
The biocompatibility and biodegradability of new magnetic resonance imaging (MRI) contrast agents is high-ly desired. The superparamagnetic iron oxide (SPIO) nanoparticles are suitable candidates for these pur-poses. Here the co-precipitation technique for synthesis of monodispersed SPIO nanoparticles is pre-sented. The critical point of the synthesis is core formation and consequent crystal growth. The conditions for core formation (time, temperature, rate of base addition) were optimised. The nanoparticles were stabilised by either silanisation or polymer coating (cationic chitosan, poly-D-Arg, dextran, gelatine, hyaluronic acid). The stability was investigated in physiological pH, different ionic strength solutions, PBS-albumine solution or blood plasma. The biocompatibility was tested in vitro either in the presence of Saccharomyces cerevisiae or erythrocytes suspension. The size and shape was investigated by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The molecular structures of nanoparticles were investigated by FTIR (Fourier transform infrared spectroscopy). The iron cations were determined using the Prussian blue staining test. The stability of nano-particles was investigated by the zeta potential using the method of electrophoretic light scattering (ELS).
|
|
|
Data acquisition and processing in ultrasound perfusion analysis
Mézl, M. ; Jiřík, Radovan ; Harabiš, V.
This study aims at absolute quantification in ultrasound perfusion analysis, which applies a general perfusion model from other modalities. Three perfusion parameters – blood flow, mean transit time and blodd volume are estimated. The method is tested on in vitro data from phantom model and preclinical data acquired from pigs heart. Estimated perfusion parameters were compared with reference values obtained from paramters of phantom model and from reference method for blood flow quatification (for preclinical data).
|
|
|
Compressed sensing for MRI perfusion imaging
Daňková, M. ; Rajmic, P. ; Jiřík, Radovan
Perfusion MRI is a diagnostic method in medicine. The signal captured from the affected area can be described by the curve of lognormal distribution. The standard way of obtaining the measurements is very slow and does not comply with today's challenging requirements. Using compressed sensing, we propose to acquire much less coefficients, having minimal effect on the signal reconstruction (using the assumption that the data is a sum of low-rank matrix and sparse matrix in row spectrum).
|
guest ::
