Three-dimensional imaging and scanning range finders using the parallax principle

A technique, for obtaining accurate, high resolution, three-dimensional range maps of scenes called the parallax principle, is discussed. Distances are obtained by measuring the separation of nearest-neighbor spots on the image plane of a camera produced by illuminating a scene with parallel beams of lines, planes, or hollow cylinders. The parallax method does not require knowledge of the location or orientation of the beam projector, nor does it suffer from the correspondence problem that plagues methods based on triangulation. Calibration and data reduction using the parallax method are considerably easier than with triangulation. A radar-type range finder for mobile robots that measures distances for all azimuths simultaneously without any mechanical motion is presented