Dynamics range enhancement in digital fringe projection technique

In this paper a new approach to enhance the dynamic range of a fringe projection system for measuring 3D profile of objects with wide variation in their optical reflections is proposed. The high dynamic range fringe images are acquired by recursively controlling the intensity of the projection pattern at pixel level based on the feedback from the reflected images captured by the camera. A four step phase shifting algorithm combined with a quality guided algorithm is used to obtain the unwrapped phase map of the object from the acquired high dynamic range fringe images. Simulation and experimental results show that the proposed technique can accurately measure the 3D profile of objects with wide variation in their optical reflectivity. (C) 2014 Elsevier Inc. All rights reserved.