New Method to Calculate Looming for Autonomous Obstacle Avoidance

摘要

The idea of visual looming, i.e., the expansion of an object's size on the retinadue to its decreasing distance from the observer, can be used as a powerful visual cue for autonomous obstacle avoidance. In this paper we describe a method of measuring looming quantitatively by fixating a camera at a point on the surface of an object and studying the texture near this point. A reduced distance of the camera from the surface results in a decline in the density of the texture primitives in the image. We show analytically how looming can be calculated from the relative change in this density and from the local orientation of the surface. The method is applicable for both stationary and moving obstacles and does not require calculation of range. Results of looming are presented for various textural surfaces, in different orientations.