TWO-STEP APPROACH TO OPTIMAL MOTION AND STRUCTURE ESTIMATION.

A two-step approach to motion and structure estimation from monocular perspective images is proposed. The approach consists of two steps. The first step is estimating the motion parameters using a linear algorithm that gives a closed-form solution for motion parameters and scene structure. The second step is minimizing errors through iteration using the solution obtained from the first step as the initial guess. Though each step by itself can generally solve the problem independently, this two-step approach is superior to each individual step in the sense that it combines the advantages and avoids the disadvantages of both steps. Using the first step, a unique solution can be guaranteed. Using the second step, an optimal solution can be obtained based on a desired criterion. The approach is applicable to any type of features. As an example, an algorithm using point correspondences is discussed in some detail and experimented with. A line-based algorithm is also discussed briefly.