Self-calibration of an On-Board Stereo-vision System for Driver Assistance Systems

Vision-based driver assistance systems need to establish a correspondence between the position of the objects on the road, and its projection in the image. Although intrinsic parameters can be calibrated before installation, calibration of extrinsic parameters can only be done with the cameras mounted in the vehicle. In this paper the self-calibration system of the IWI (intelligent vehicle based on visual information) project is presented. It pretends to ease the process of installation in commercial vehicles. The system is able to self calibrate a stereo-vision system using only basic road infrastructure. Specifically, only a frame captured in a straight and plane stretch of a road with marked lanes is required. Road lines are extracted with the Hough transform, and used as a calibration pattern. Then, a genetic algorithm finds the height, pitch and roll parameters of the vision system. The user must run this algorithm only once, unless the vision system is replaced or reinstalled in a different position