A pseudo-interferometric laser range finder for robot applications

Abstract

A description is given of a low-cost laser ranger suitable for robot applications. The region to be observed is illuminated by a sinusoidal intensity distribution generated by an optical projection system with a laser source. The deformation of the sine-wave pattern is detected by a phase-sensing method widely used in optical interferometry, and can be easily related to the shape and range information. Over a range determined by the depth of field of the camera at a given aperture and focal setting, high-resolution measurements can be made. Experimental results show that at a camera distance of about 1 m, the resolution and repeatability in locating a flat 25-mm/sup 2/ surface are of the order of 0.2 mm.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>