A three-dimensional profile measurement system based on a projection coded grating technique is presented. The system uses a designing and decoding technique for grey coded gratings. The coded grating has black, white and grey stripes. The period triples a conventional grating. It greatly increases the height measuring range without any decrease in stripe separation. The shape of object can be obtained from only one grating image. The system is suitable for instantaneous measurement of moving objects including human face. The technique proposed permits rapid 3D measurement and no moving parts are involved in the system. The hardware is relatively simple. Special data processing software is developed. Results of a practical example confirm the effectiveness of the proposed method.
