Quantitative interpretation of image velocities in real time

A concept for motion stereo is introduced. It is based on an explicit determination of the velocities with which features move in images of dynamic scenes. A mobile robot carrying a single TV-camera may use this method to determine its distance to external objects accurately and in real time. While the robot approaches an object the accuracy of the measurement improves continuously as the distance decreases, making the method particularly suitable for tasks like collision avoidance or docking. The method may be implemented in such a way that it does not require a camera calibration, provided the lens of the camera is sufficiently free from distortion. The method has been applied on a mobile robot equipped with a real-time vision system, and experiments have been performed to test its practicality in a real-world environment. Accuracies better than 1% of the distance have been demonstrated while the robot was moving in the direction towards the object.<>