The Bilateral Grid and a Topological Approach to Image Segmentation


April 20, 2007


Sylvain Paris


Massachusetts Institute of Technology


I will present our latest results on image and video processing. First, I will introduce the bilateral grid, a new image representation that enables fast edge-aware image processing. Image data is stored in a coarse 3D grid where an intensity axis is added to the traditional x and y axes. By working in the bilateral grid, algorithms such as bilateral filtering, edge-aware painting, and local histogram equalization become simple and can be efficiently parallelized on modern graphics hardware to achieve real-time performance on HD video. I will demonstrate our method on a variety of applications such as image editing, transfer of photographic style, and contrast enhancement of medical images. In a second part, I will present a new interpretation of the mean-shift algorithm for image and video segmentation. I will show that a mean-shift segmentation is equivalent to a topological decomposition of the underlying feature space. Using Morse theory and the notion of topological persistence, this decomposition is used to build a hierarchical segmentation of the data at a negligible computational cost. Our experiments demonstrate that our algorithm achieves the same accuracy level as existing techniques while being significantly faster for high-resolution images and videos for large kernels.


Sylvain Paris

Sylvain Paris graduated from École polytechnique in France and has a masters degree in Algorithmics. For his PhD, he was advised by François Sillion at INRIA in Grenoble, France. He also collaborated with Long Quan from Hong Kong University of Science and Technology where he spent six months. Since November 2004, he is a postdoctoral associate at the Massachusetts Institute of Technology in Boston where he is working with Frédo Durand. His research interest is at the interface between Computer Vision, Image Processing and Computer Graphics. More precisely, he has contributions in the fields of 3D reconstruction from images, three-dimensional capture of hair, and computational photography.