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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.
1

Fokusace očí na charakteristické prvky vizuálního vjemu / Focusation of eyes on characteristic component of visual perception.

Fejgl, Martin January 2011 (has links)
This master’s thesis deals with muscles physiology of eye movement and questions of surface electromyography measurement. Physiology and analysis of eye movement are described here. Furthermore the paper deals with a variety of electrooculographic measuring techniques and also with resulting evaluation of measured signal.
2

Úroveň přesnosti hodu na vertikální cíl v závislosti na kombinaci zkřížené a souhlasné laterality ruka oko u vybrané populace studentů FTVS. / Accuracy in throwing on the vertical target depending on combination of crossed and identical hand - eye laterality in selected population of FTVS students

Studnař, Lukáš January 2014 (has links)
Title: Accuracy in throwing on the vertical target depending on combination of crossed and identical hand - eye laterality in selected population of FTVS students. Objectives: The aim of this study is determination of any disparity in success rate and darts distribution among selected strongly right-handed and left- handed population of male and female students of FTVS in throwing on the vertically positioned target. Methods: The main research method was used descriptive association method. A total of 60 individuals were enrolled in the study. We used Musalek's test battery (2013) containing questionnaire part, preferential tasks and proficiency tests to define particular sidedness of individual probands. Further a specific task of the throw at the target was employed. For data analysis we used descriptive statistics methods, chi-squared test goodness of fit, analysis of variance, tetrachoric correlation and level of substantive significance expressed by Cohen's d. Results: The results indicated that left-handed individuals did not show a significantly better accuracy in throwing at the vertically positioned target compared with right-handed individuals. It seems that gender is an important factor that affects the level of accuracy in the throws on target because male showed significantly better...
3

Biotribologie umělých slz pro léčbu syndromu suchého oka / Biotribology of artificial tears for the treatment of dry eye syndrome

Černohlávek, Mikuláš January 2021 (has links)
This master thesis is a part of the project TAČR TREND, which aim is the development of new ingredient for treatment of dry eye syndrome. Developed ingredient is derivative of hyaluronic acid, which is in this thesis compared with native hyaluronic acids and commercial eye drops. Aim of this thesis is to describe rheological and tribological properties of measured samples in terms of viscosity, mucoadhesivity and coefficient of friction. Coefficient of friction was measured on created tribological model of the eye in pin-on-plate configuration which represents physiologically relevant sliding speeds of blinking. Comparison with native hyaluronic acids and commercial products of eye drops showed, that derivative reaches higher values of viscosity, has mucoahesive properties and has low values of coefficient of friction. Those key parameters show that modification of hyaluronic acid is promising way for drug development for dry eye disease.
4

Lícování snímků sítnice pomocí metody fázové korelace / Retinal image registration using phase correlation

Šikula, Viktor January 2011 (has links)
This master thesis deals with retinal image registration using phase correlation technique. There are described properties of retinal images and modality of scanning. A geometrical transformation encompasing scale, rotation and translation between two retinal images is considered and the whole registration framework is described. There are used retinal images from fundus camera and scanning laser ophthalmoscope (SLO). In this thesis is described corresponding bifurcations detection using phase correlation and registration using second-order polynomial transformation. The results are subjectively and objectively verificated.
5

Segmentace optického disku ve snímcích sítníce / Optic disc segmentation in retinal images

Vymazal, Bronislav January 2013 (has links)
Cílem této práce bylo vytvořit kompaktní algoritmus sloužící k lokalizaci, segmentaci a sledování optického disku v sekvencích obrazů sítnice. Pro účely lokalizace byla použita nová metoda založena na „fast radial transform“. Segmentace optického disku je založena na klasické metodě Chan-Vese, která byla rozšířena o další prvky a implementována v lokalizované podobě, která umožňuje lépe segmentovat obrazy s vysokou mírou nehomogenity. Pro sledování optického disku v sekvencích obrazů byl využit optický tok založený na Lucas-Kanade algoritmu. Všechny metody byly vyhodnoceny na dvou databázích obrazů s odlišnými charakteristikami. První databází je klasická databáze s vysokým rozlišením. Druhou je pak databáze s nízkým rozlišením a vysokou mírou šumu. Všechny výsledky jsou pak porovnány s referenčními hodnotami a vyhodnoceny.
6

Extrakce krevního řečiště z Fundus snímku lidského oka. / Extraction of arteries and veins from fundus image of human retina.

Pinkava, Marek January 2014 (has links)
This thesis deals with processing of retinal fundus images. Vision is the most important human sense and its injury has very serious consequences for humans. Automatic processing of retinal images increases the efficiency of medical examination and accelerates diagnoses of deseases. Retina exhibits unique characteristics for each person and thus can also be used to identify people. In this task is briefly discussed the structure and properties of each parts of the eye, particularly the retina, and their possible diseases such as diabetic retinopathy, glaucoma and age related macular degeneration. Subsequently, the task describes the representation and characteristics of the digital image. Also is devoted to selected image segmentation methods namely thresholding, edge detection and segmentation techniques based on the matched filter. The outcome of this task is the application in which several segmentation methods are implemented for the blood vessels extraction. For each of these methods it is possible to set the parameters of the segmentation to ensure high quality blood vessels extraction in images of different quality.
7

Ekologické faktory ovlivňující variabilitu ultrafialového zbarvení květů / Ecological factors influencing variability of ultraviolet colouration of flowers

Zitko, Martin January 2019 (has links)
Ultraviolet colouration of flowers varies both among and within species. The significance of these patterns and differences among them was usually associated with a visual per- ception of pollinators. In this study we examine the variation of marsh marigold's (Caltha palustris) bull's-eye pattern on a basis of 289 observed individuals from 32 distinct locati- ons. The variation of this pattern is shown to be quite large within separate locations and the pattern is predictably changing according to latitude. This trend of darker colouration towards the equator is an another example of a more widely understood Gloger's rule in the plant kingdom. The effect of ultraviolet radiation appears to be one of the most likely causes of this phenomenon. Hereafter we analyse the weakness of this explanation, the gaps in current knowledge and propose possible directions of further research. Keywords: ultraviolet, bull's-eye, marsh marigold, Caltha palustris, Gloger's rule
8

Evoluce vnímání světla u strunatců / Evolution of light detection in chordates

Pergner, Jiří January 2018 (has links)
Light detection is one of the crucial abilities of all animals. The light cues are important e.g. for maintaining of circadian rhythms, regulation of spawning cycles, changes of pigmentation and arguably most importantly for vision. Most animals detect light by opsins, members of the G protein coupled receptors superfamily. Amphioxus belongs to earliest branching chordate clade, cephalochordates. Thanks to their phylogenetic position, physiology and morphology, cephalochordates became the most relevant model organism for understanding the evolutionary origins of vertebrate specific traits. Amphioxus evince various reactions to light throughout its development. In the presented thesis light detecting systems of amphioxus were studied thoroughly. More specifically characterization of the opsin gene repertoire of two amphioxus species Branchiostoma floridae and Branchiostoma lanceolatum and their comparison with opsins from other animals is presented. In addition, remarkable similarity on the gene expression level between one of amphioxus visual organs, so called frontal eye, and neurons and retinal pigmented epithelium in vertebrate retina was shown. These data confirm the long time ago proposed homology between amphioxus frontal eye and vertebrate lateral eyes. Taken together all the presented data...
9

Vliv plasmové nitridace na únavovou životnost vysocepevných ocelí při biaxiálním zatěžování / Influence of Plasma-nitriding on Fatigue Life of High-strength Steels under Biaxial Loading

Major, Štěpán January 2010 (has links)
This work deals with fatigue life and fractographycal analysis of plasma-nitrided and virgin specimen made of the low-alloy high-strength steel. Specimens were subjected to in-phase combined bending-torsion loading. The work is focused on three groups of problems. The first group of problems was associated with the fatigue life and its prediction. The objective was to examine a relationship between the presence of the nitrided layer and fatigue life. The application of surface layers has significantly improved the fatigue life in the high-cycle region. An extended comparison between classical and advanced multiaxial criteria was performed. Criterions proposed by Marin and Matake were found to be most precise. The second objective of this work was to examine a relationship between the loading ratio ( is the bending amplitude and is the torsion amplitude ) and the fracture surface topography in the highcycle fatigue. Properties of fracture surfaces were quantified by many roughness and fractal parameters. Many roughness parameters start to incrise rapidly above a critical value of the loading ratio zc = 0,5. The last part of this work deals with the fractographical analysis of fish-eye cracks that were formed in plasma-nitrided steel specimens under symetrical bending, symetrical torsion and biaxial in-phase bending-torsion combinations.
10

Fotobiologická bezpečnost svítidel a světelných zdrojů / Photobiological Safety of luminaires and Light Sources

Štěpánek, Jaroslav January 2020 (has links)
This doctoral thesis called “Photobiological safety of luminaires and light sources” has focused on an optical radiation and its relation to human body. The thesis describes possible consequences on living tissue during excessive exposure to optical radiation. Among others the work deals with the light source, lamp and optical devices evaluation in dependence of photobiological safety. There is created a method of light source evaluation procedure for photobiological safety in accordance with ČSN EN 62471. The meaning of this procedure is based on its hazard calculation from measured values of irradiation to different photometric distances. Validity of procedure is verified by light source measuring, in which visual angle and photometric distance have been changed. There we can also find an application of this procedure in the UV source evaluation, which helps to determine a safe distance away from UV sources not to create any danger. The evaluated UV sources include a UVA luminaire with a dominant wavelength of 365 nm or an arc of an electric welder. The thesis also describes a method of evaluating light sources for blue light hazard for an aphakic and pseudophakic eye. This method can also help to determine the hazard for the eye without lens or with some implanted lens. Furthermore, there was developed the method of the blue light hazard assessment depending on the age of an exposed person. In terms of the work there was also created a computer programme evaluating photobiological safety resulting from the spectral data having been stored in the library programme or from spectroradiometric measurement data. The work also marginally deals with the topic of circadian rhythms, which are closely related to photobiological manifestation in an human body. Above all the work compares light sources for which equivalent illuminances are calculated, consequently light sources have the same effect on suppressing the melatonin hormone production.

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