Robust obstacle detection in general road environment based on road extraction and pose estimation

This paper proposes a method of obstacle detection using vehicle-mounted stereo cameras. There are various objects in the road environment; these can be divided into objects, such as pedestrians, which have the possibility of colliding with the vehicle, and objects, such as road patterns, which do not have such a possibility. In this paper, an obstacle is defined as an object which is located in the space through which the vehicle will travel. In order to decide whether an object is an obstacle from the pattern in the image, it is necessary to estimate the position of the pattern in relation to the road surface. For this purpose, the planar region is determined by dynamically estimating the homography (projection transformation) matrix between the images corresponding to the plane. The pose of the camera with respect to the road is determined. Then the spatial position obtained by stereo measurement is converted to road coordinates, based on the orientation of the road surface. By applying segmentation based on the converted result of stereo measurement, obstacles are detected. On ordinary roads it is required to detect various obstacles, ranging from relatively small obstacles such as pedestrians and bicycles to large obstacles such as cars. The proposed method can detect obstacles without explicit modeling. The effectiveness of the proposed method is demonstrated by experiments using various actual images. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(12): 12–22, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20413