Multi Light Sources Range Finder System

Abstract

This paper describes a new range finder system which projects multi light planes. The purpose of the system is to get 3-D data of objects at high speed and with high accuracy. To realize the purpose two new techniques are introduced. One of the techniques is its optical system: each light source is composed of a laser diode and a cylindrical lens, and projects a light plane on the object. Fifteen light sources are located on a circle around a rotating mirror so that light planes are converged on the axis of rotation. A CCD camera takes the image of the light planes projected via the mirror. For each rotation angle, the light sources are turned on and off according to a specified code so that the light sources can be identified from the image data. Then, the mirror rotates to project light planes to other parts of the object. Another technique is the pre-processing circuit: it converts, in real time, video data from camera into reliable 2-D information of light planes appearing in the image. Due to the result that essential information is extracted with the circuit, size of output is drastically reduced. In this process, the 1/10 pixel accuracy of detected position data is achieved with a special interpolation scheme by a hard-wired computing circuit.