On the computation of the ego-motion and distance to obstacles for a micro air vehicle

In this paper, we have considered the problem of velocity and range estimation for an UAV using a camera and the knowledge of linear speed through a GPS device. In our earlier work (2006), a method for decomposition of a scene into structure blocks, and finding correspondences between such blocks in successive frames was developed. The result of this low-level image processing is (a) a set of structure blocks; (b) the motion of each structure block; and (c) a reliability index between zero and one denoting the confidence of the solution in (b). Here, we show that by solving a constrained optimization problem set up using the results of the image processing, one can obtain the linear and angular velocity of the camera motion, provided the speed of the linear motion is known. Once the velocity parameters is computed, we show how the range to objects in the field of view can be computed