This paper describes 3D vision techniques for an advanced robot system in terms of efficient hardware and practical software. Arm-controlled stereo cameras have been developed for efficient 3D sensing, whose interocular distance, yaw and tilt are under program control. Stereo vision programs are implemented with the aid of the stereo cameras and a high-speed vision processor. Knowledge-guided vision algorithms are realized in a high-level processor, where a priori knowledge regarding the environments, objects and procedure controls are utilized.