Simple gamma correction for fringe projection profilometry system

Fringe projection profilometry (FPP) is one of the most commonly used non-contact methods for retrieving the three-dimensional (3D) shape information of objects. In reality, the nonlinearity mostly caused by the gamma effect of digital otpic system, includes both projector and camera, gives inevitable intensity changes, which dramatically reduce the measurement accuracy. In this poster, a robust and simple scheme to eliminate the intensity nonlinearity induced by gamma effect. Firstly, by using phase shifting techniques, the gamma value involved in the measurement system can be detected accurately. Then, a gamma encoding process is applied to the system for future actual 3D shape measurements. With the proposed technique, high accuracy of measurement can be achieved with the traditional three-step phase-shifting algorithm.