Detecting unexpected moving obstacles that appear in the path of a navigating robot

Presents a system that detects unexpected moving obstacles that appear in the path of a navigating robot, and that estimates the relative motion of the object with respect to the robot. The system is designed for a robot navigating in a structured environment with a single wide-angle camera. The system uses polar mapping to simplify the segmentation of the moving object from the background. The polar mapping is performed with the focus of expansion (FOE) as the center, obtained from the vanishing point of the significant lines in the environment. A method for determining a qualitative estimate of the motion of the object, coupled with an efficient clustering algorithm, is used to segment the moving obstacle from the background. The system uses an area based feature matching method to compute the optical flow in the segmented regions of the image sequence, and time-to-impact is computed from the radial component of the optical flow in the image plane. A framework for a real time implementation of this system on a robot is also presented