An Effective Active Vision System for Gaze Control

Abstract

This paper presents the performances of an active vision system that mimic the human gaze control. A human can shift his gaze either by quickly moving his fixation point or by keeping a moving target in the fovea (high resolution). These two visual phenomena are called saccadic and smooth pursuit eye movements respectively. In order to mimic this human behavior, we have developed a novel active vision system based on a particular stereo-vision setup. It is composed with one camera, one prism and a set of mirrors. To point the field of view of the sensor at a target, the prism is rotated about its axis by a motorized stage. The system is designed for fast and accurate dynamical adjustments of gaze.To study the mechanical performances of our active vision system we have used three different but classical input signals. A step signal that simulates a change of target (saccadic eye movement), a velocity ramp and a sinusoidal signal that simulate a moving target (smooth pursuit). Whatever the input signal, the objective is to maintain the target in the middle of the image. The experiments demonstrate the efficiency of our vision sensor, in term of dynamical properties and measurement accuracy.

A visual attention focusing system using an active stereoscopic vision sensor

“…To make a decision, we will compute a cost coefficient λ ij which is proportional to the time required to bring the motorized stage from the angular position i to the angular position j: λ ij = αij ∆α , with ∆α the maximum angle of rotation authorized for the prism. α ij is calculated from the mechanical specifications of the stereocopic sensor [24]. A priority coefficient p i is then affected to the region to explore.…”