Reconstruction of quadric surface from occluding contour

We present an algebraic method to reconstruct quadric surfaces from occluding contours observed in two images. The occluding contour is the image of a special curve, called rim, on the surface. It is defined by the fact that the optical rays of their points are tangential to the surface. We show that, although the occluding contours in two images do not correspond to the same rim on the surface, we can reconstruct the surface from its two images by solving three quadratic equations. Our method has been successfully tested by the simulated data and by the real image data.