High dynamic range 3D shape measurement based on the intensity response function of a camera.

Fringe projection profilometry has been widely used in many fields for its advantages such as high speed, high accuracy, and robustness to environmental illumination and surface texture. However, it is vulnerable to high dynamic range (HDR) objects. To this end, we propose a technique that can enhance the dynamic range of the fringe projection profilometry system. According to the surface reflectivities of the measured objects, several groups of fringe patterns with optimal light intensities are generated based on the intensity response function of a camera. The HDR fringe images are acquired by fusing these fringe patterns, and a three-step phase-shifting algorithm is used to obtain the unwrapped phase from the fused images. Experimental results demonstrate that the proposed technique can accurately measure objects with an HDR of surface reflectivity variation.