Topologically correct cortex segmentation
Automatic detection and correction of topological segmentation errors by cutting handles or filling holes. Topological errors can result from erroneous inclusion or exclusion of voxels in the binary segmentation. The topological correction can therefore consist in removing voxels (cutting the handle, red) or adding voxels (filling the hole, yellow). The figure shows both solutions as computed by distance-to-surface prioritized, selftouching-sensitive region growing. The algorithm chooses the better solution for each topological defect separately by a heuristic (Fig. 5). In this case, it has chosen to fill the hole. Though the algorithm operates in voxel space, surface renderings have been used to visualize the intermediate and final results. Whereas for the cut (red) and the filling (yellow) the surfaces reflect the cubic shape of the voxels, the polygon meshes representing the pre- and postsegmentation (blue) have been smoothed to ease visual orientation.