Figure 11: (a) Diagram of an object with intensity 1 between two regions of intensity 9, showing set of pixels (bold) whose spheres contain pixel . This set produces an vector (see text) along which the furthest bold pixel is the center of a medial sphere (circle in bold) touching both boundaries (dashed lines). (b) Image of a 2D slice through a CT scan of the aorta with contrast showing an actual set (purple), the resulting vector, and the medial manifold (dashed curve) on which the furthest sphere along must lie.
