Color-encoded fringe projection and phase shifting for 3D surface contouring

A color-encoded fringe projection and phase shifting technique is proposed for rapid 3-D surface contouring applications. A color fringe pattern whose RGB components comprise three phase-shifted fringe patterns is created by software on a computer screen and then projected to an object by a novel computer-controlled digital projection system. The image of the object is captured by a digital camera positioned at an angle different from that of the projection system. The image is then separated into its RGB components, creating three phase-shifted images of the object. These three images are used to retrieve the 3-D surface contour of the object through the use of a phase wrapping and unwrapping algorithm. Only one image of the object is required to obtain its 3-D surface contour. Thus contouring speed, limited only by the frame rate of the camera, can be dramatically increased as compared to that of the traditional phase shifting techniques. The technique is especially useful in applications where the object being contoured is going through quasi-static or dynamic changes. This paper describes the principle of the technique and presents some preliminary experimental results.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.