Experience in using homotopy methods to solve motion estimation problems

We consider the problem of determining motion (three-dimensional rotation and translation) of rigid objects from their images taken at two time instants. The locations of the perspective projection of each of n feature points onto the image plane from the surface of the rigid body are assumed to be known at those times. We state some results of previous work, and in the important n = 5 case show how all the solutions can be obtained nearly six times as quickly as before. In the cases n = 6 and n = 7, all the solutions can be obtained approximately fifteen and thirty times more quickly, respectively, than by the previous method.