Evaluation of a real-time kinetic depth system

Abstract

We describe a robot vision system which produces a depth map in real time by means of motion parallax or kinetic depth. A video camera is held by a robot which moves so that a given point in space is kept fixated on the centre of the camera's imaging surface. The optical flow is calculated in a Datacube MaxVideo system and a full-frame depth map is produced 12.5 times per second. Calculated depths show an average 10% discrepancy with measured depths over 7 nonconsecutive images. sponding to the direction of the target point which are closer to the robot than the target point would indicate the presence of an obstacle. The first step in this process is the construction of the kinetic depth system and the second step is to evaluate its sensitivity to system parameters. We describe the kinetic depth system here and give preliminary results of the evaluation. For an observer fixating a point in space and moving perpendicularly to the direction of gaze, objects in front of the fixation point appear to move in the opposite direction and objects behind the fixation point appear to move in the same direction. The speed of apparent motion is proportional to the distance of the object from the fixation point. This phenomenon is known as kinetic depth. If the parameters of the observer's optical system and the details of the observer's motion and fixation point are known, then measurements of the speed and direction of apparent motion of an image point (optical flow) give the distance of the corresponding object point from the observer.