A method and system to enable a computer to estimate calibration parameters autonomously so that accurate stereopsis can be performed. The present invention automatically calibrates two or more cameras with unknown parameters with respect to a robot or robotic appendage (e.g., articulated robot arm) with a light source that can be turned on and off at one end. A pair of cameras (e.g., digital cameras) are positioned and aimed so as to give stereoptic coverage of the robot's workspace. The procedure determines the positions and orientations of the pair of cameras with respect to a robot (i.e., exterior orientations) and the focal lengths, optical centers, and distortion coefficients of each camera (i.e., intrinsic parameters) automatically from a set of known positions of the robot arm, and a set of images from the right and left cameras of the robot arm in each position as the light is turned on and off.