Tracing planar surface motion from a projection without knowing the correspondence

Abstract The 3-dimensional motion of a planar surface is detected only from the motion of its projected 2-dimensional contour image on the plane of vision. There is no need to know the correspondence of points. The motion is explicitly given by measuring “diameters” of the image contour on the plane of vision. No iterative or matching processes are involved. Numerical examples are also given.