“Rainbow Range Finder”is a method for rapidly acquiring 3D information based on spectral analysis. It uses a special light with continuous spectrum to project across the objects

and its image will present the regular change of colors. One color forms a line in the color image and responds to a light plane structured by a wave band in the spectrum. When all the light planes are calibrated and the camera model is known

we can calculate 3D coordinates of all image points in the scene. This paper mainly discusses the light plane calibration and color classification techniques for implementation of these methods.