Ellipse Detection

Práce představuje algoritmy používané pro detekci elipsy v obraze. Každá metoda je teoreticky popsána ve vlastní podkapitole. Mezi popisované metody patří mimo jiné Houghova transformace, Náhodná Houghova transformace, RANSAC, genetické algoritmy a jejich různé úpravy a optimalizace. Dále jsou popsány modifikace stávajících postupů s cílem dosažení lepších výsledků, jedná se o Obloukovou MHT, Kombinaci NMHT a Detekci metodou nejmenších čtverců. Předposlední kapitolou je popis testování parametrů rychlosti, úspěšnosti a přesnosti implementovaných algoritmů. Závěr práce shrnuje výsledky dosažené testováním a jednotlivé metody komentuje.The thesis introduces methods used for an ellipse detection. Each method is theoretically described in current subsection. The description includes methods like Hough transform, Random Hough transform, RANSAC, Genetic Algorithm and improvements with optimalization. Further there are described modifications of current procedures in the thesis to reach better results. Next to the last chapter represents testing parameters of speed, quality and accuracy of implemented algorithms. There is a conclusion of testing and a result discussion at the end.

Microsphere Traction Force Microscopy

This work is a culmination of our efforts in understanding cellular mechanics at the scale of single cells and small tissues. We developed methods to quantify cell-generated traction forces using cell-sized, synthetic, functionalized hydrogel microspheres. Cell-sized solid microspheres can provide information regarding cell-generated normal and shear forces while allowing natural cell-cell interactions and facilitating a convex cell-hydrogel interface. Therefore, they are a better mimic than the current methods for understanding the natural cell-cell interactions in a physiologically relevant geometry. In the analysis of the microsphere deformations, we use a boundary spectral method based on spherical harmonics decomposition of the traction field on the spherical gel surface. Using the techniques developed here, we measure the boundary traction profiles that mammalian cells exert on the synthetic microspherical hydrogel bodies. In this report, we briefly review the state of the art in cellular force quantification methods and discuss the contributions of our work to the field and its strengths as well as its limitations