Three-dimensional motion estimation from image-space shifts

We present a two-step method of estimating the parameters of general three-dimensional motion of rigid bodies based on two time-sequential perspective views. The first step is to estimate the image-space shifts of a number of points. Then, the second step is to determine the motion parameters from these shifts. The second step involves the solution of equations where the unknowns can be partitioned into two subsets appearing bilinearly. An iterative method for solving such equations is suggested. In the special cases of three-dimensional translation and of two-dimensional motion with zooming, the equations become linear.