Feature preserving smoothing of 3D surface scans

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2004.Includes bibliographical references (p. 63-70).With the increasing use of geometry scanners to create 3D models, there is a rising need for effective denoising of data captured with these devices. This thesis presents new methods for smoothing scanned data, based on extensions of the bilateral filter to 3D. The bilateral filter is a non-linear, edge-preserving image filter; its extension to 3D leads to an efficient, feature preserving filter for a wide class of surface representations, including points and "polygon soups."by Thouis Raymond Jones.S.M

Predicting gene function from images of cells

Thesis (Sc. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (p. 107-118).This dissertation shows that biologically meaningful predictions can be made by analyzing images of cells. In particular, groups of related genes and their biological functions can be predicted using images from large gene-knockdown experiments. Our analysis methods focus on measuring individual cells in images from large gene-knockdown screens, using these measurements to classify cells according to phenotype, and scoring each gene according to how reduction in its expression affects phenotypes. To enable this approach, we introduce methods for correcting biases in cell images, segmenting individual cells in images, modeling the distribution of cells showing a phenotype of interest within a screen, scoring gene knockdowns according to their effect on a phenotype, and using existing biological knowledge to predict the underlying biological meaning of a phenotype and, by extension, the function of the genes that most strongly affect that phenotype. We repeat this analysis for multiple phenotypes, extracting for each a set of genes related through that phenotype, along with predictions for the biology of each phenotype. We apply our methods to a large gene-knockdown screen in human cells, validating it on known phenotypes as well as identifying and characterizing several new cellular phenotypes that have not been previously studied.by Thouis Raymond Jones.Sc.D