Real-time high-dynamic-range fringe acquisition for 3D shape measurement with a RGB camera

This paper introduces a novel real-time, high-dynamic-range (HDR) three-dimensional (3D) shape measurement method using a RGB camera. The proposed method takes advantage of two effects to realize HDR 3D fringe acquisition for 3D shape measurements: (1) the different responses of a RGB camera's three channels to a single color light source can be utilized to produce fringe images with different intensity levels; (2) the projector's dark time can be utilized to produce bright versus dark intensity contrast if bit-wise binary patterns are used. Experiments demonstrate the real-time capabilities of the proposed method by dynamic 3D shape measurements (with a maximum camera frame rate of 166 Hz). Given that a bit-wise defocused binary pattern projection is adopted, the proposed HDR method has the potential for high-speed applications if a high-speed color camera is present.