Development of 3-D position measurement method for a round hole

In this paper novel methods to measure the three-dimensional position of the round hole are presented. The round holes are widely used as a reference with the positioning of the automobile body construction process. We have developed a sensor composed of a TV camera and two laser slit light sources for measuring the 3D position of the round hole. The sensor measures the coordinates of four points on a circumference of round hole using triangulation method. By combining the slit image and the round hole image, four points are detected with high accuracy. In the experiment, position measurement accuracy 0.1mm or less (Working distance 200mm) are obtained and confirmed the basic performance of the developed sensor.