<title>Autonomous obstacle avoidance using visual fixation and looming</title>

Abstract

This paper describes a vision-based method for avoiding obstacles using the concepts of visual looming and fixating motion. Visual looming refers to the expansion of images of objects in the retina. Usually, this is due to the decreasing distance between the observer and the object. An increasing looming value signifies an increasing threat of collision with the object. The visual task of avoiding collision can be further simplified by purposive control of visual fixation at the objects in front of the moving camera. Using these two basic concepts real time obstacle avoidance in a tight perception-action loop is implemented. Three-dimensional space in front of the camera is divided into zones with various degrees of looming-based threat of collision. For each obstacle seen by a fixating camera, looming and its time derivative are calculated directly from the 2-D image. Depending on the threat posed by an obstacle, a course change is dictated. This looming based approach is simple, independent of the size of the 3-D object and its range and involves simple quantitative measurements. Results pertinent to a camera on a robot arm navigating between obstacles are presented.