Live Surface

Live Surface allows users to segment and render complex surfaces from 3D image volumes at interactive (subsecond) rates using a novel, cascading graph cut (CGC). The process consists of four steps. (1) Preprocessing for generation of a complete 3D watershed hierarchy followed by tracking of all catchment basin surfaces. (2) User selection of foreground and background seeds from two-dimensional, image cross-sections. (3) Segmentation of the volume by cascading through the 3D watershed hierarchy from the top, applying graph cut successively, at each level, only to catchment basins bordering the segmented surface from the previous level. (4) OpenGL rendering for display and update of the segmented surface at interactive rates. CGC allows the entire image volume to be segmented an order of magnitude faster than existing techniques that make use of graph cut. Segmentation and rendering, combined, is accomplished in about 0.5 seconds, allowing 3D surfaces to be displayed and updated dynamically as each additional foreground seed is deposited. CGC allows the user to control and steer the segmentation with immediate user feedback, providing a Live Surface tool for 3D image volumes similar to the Live Wire (Intelligent Scissors) tool used in 2D images.