Surface discontinuities in range images

The authors present a formulation of discontinuity detection in range images. The emphasis is on roof edge detection which is evaluated as C/sup 1/ discontinuity strength at every point in the range image. Contrary to other local approaches, it is possible to detect all shapes of C/sup 1/ discontinuity from one polynomial approximation even when the viewpoint changes. First, the range data are locally approximated by a second-order bivariate polynomial. Second, the 2-D problem of surface discontinuity strength estimation is converted to a 1-D probem along the direction of maximal normal curvature at each point on the surface. Third, C/sup 1/ is computed by comparing the polynomial approximation of data and the polynomial approximation of the discretized model of the discontinuity.