Abstract: A robot vision system for outputting a disparity map includes a stereo camera for receiving left and right images and outputting a disparity map between the two images; an encoder for encoding either the left image or the right image into a motion compensation-based video bit-stream; and a decoder for extracting an encoding type of an image block, a motion vector, and a DCT coefficient from the video bit-stream. Further, the system includes a person detector for detecting and labeling person blocks in the image using the disparity map between the left image and the right image, the block encoding type, and the motion vector, and detecting a distance from the labeled person to the camera; and an obstacle detector for detecting a closer obstacle than the person using the block encoding type, the motion vector, and the DCT coefficient extracted from the video bit-stream, and the disparity map.