An active vision system for mobile robots

An Active Vision System enables the selective capture of important information for various applications. With an active vision system, the control of gaze direction toward a visual target can simplify many of the robot's interactions with the world. This work presents the implementation of a camera head control system for a mobile robot, called HelpMate. Helpmate's binocular head composes of two Song color cameras mounted on two independent pan-tilt heads. The camera tread control behaviors are designed to be similar to those of human eyes, which include saccade, smooth pursuit, vergence, and vestibulo-ocular reflex. Saccade allows the robot to quickly direct its gaze to the target, smooth pursuit keeps both cameras fixated on the moving target, vergence makes sure that the two cameras are looking at the same object, and vestibule-ocular reflex compensates the camera motion for the robot body's movement. Control methods have been designed and tested through experimentation. By using color segmentation, HelpMate can detect and locate a human holding a specific colored object, who is approaching within its range. Once the target is located, the two cameras are fixated, and HelpMate's body turns toward the target. The camera head then smoothly tracks the moving target and guides the robot to follow the target as it moves.