A digital vision chip is a one-chip vision system that can perform operations much faster than the video rate (NTSC 30 Hz/PAL 25 Hz). The digital vision chip has a compact design for integration, and can execute several algorithms at high speed for robot control. To realize high-speed image processing on digital vision chips, it is important to develop image processing algorithms that work with the processing architecture. While most of the researches on vision chips have concerned image-to-image processing, there has been few researches on image-to-scalar feature extraction which is inevitable for visual feedback control. In this paper, we propose bit-plane feature decomposition (BPFD) as a method of image-to-scalar feature extraction in digital vision chip systems. We show the effectiveness of the proposed method by evaluating its application in a digital vision chip system.