Interactive segmentation of image volumes with Live Surface
Live Surface allows users to segment and render complex surfaces from 3D image volumes at interactive (sub-second) rates using a novel, cascading graph cut (CGC). Live Surface consists of two phases: (1) preprocessing for generation of a complete 3D hierarchy of tobogganed regions followed by tracking of all region surfaces; (2) user interaction in which, with each mouse movement, the volume is segmented and the 3D object is rendered at interactive rates. Interactive segmentation is accomplished by cascading through the 3D hierarchy from the top, applying graph cut successively, at each level, only to regions bordering the segmented surface from the previous level. CGC allows the entire image volume to be segmented an order of magnitude faster than existing techniques that make use of graph cut. OpenGL rendering provides for display and update of the segmented surface at interactive rates. The user selects objects by tagging voxels with either foreground (object) or background seeds. Seeds can be placed on image cross-sections or directly on the 3D rendered surface. Interaction with the rendered surface improves the user's ability to steer the segmentation, augmenting or subtracting from the current selection. Segmentation and rendering, combined, is accomplished in about 0.35s, allowing 3D surfaces to be displayed and updated dynamically as each additional seed is deposited. The immediate feedback of Live Surface allows the segmentation of 3D image volumes using an interaction paradigm similar to the Live Wire (Intelligent Scissors) tool used in 2D images.
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