Toward a surface primal sketch

This paper reports progress toward the development of a representation of significant surface changes in dense depth maps. We call tile representation the Surface Primal Sketch by analogy with representations of intensity changes, image structure, and changes in curvature of planar curves. We describe an implemented program that detects, localizes, and symbolically describes: steps, where the surface height function is discontinuous, and roofs, where the surface is continuous but the surface normal is discontinuous. We illustrate the performance of the program on range maps of objects of varying complexity.