A new method to calculate looming for autonomous obstacle avoidance

The concept of visual looming can be used as a powerful visual cue for autonomous obstacle avoidance. In this paper a method that measures looming quantitatively by fixating a camera at a point on the surface of an object is presented. It is based on studying the texture and its temporal change near the fixation point. The surface may be tilted relative to the optical axis. Looming can be calculated from the relative change in texture density and from the local orientation of the surface. The orientation is obtained from a set of one-dimensional directional densities of the texture primitives. This visual cue is used as a feedback signal of a closed loop system to implement obstacle avoidance using a six-degree-of-freedom simulator