W. Lohry* and S. Zhang, "3D shape measurement with 2D area modulated binary patterns," Opt. Laser Eng. 50(7), 917-921, 2012; doi: 10.1016/j.optlaseng.2012.03.002
This paper presents a novel area-modulation technique for three-dimensional (3D) shape measurement with binary defocusing. Specifically, this technique modulates local 2*2 pixels to create five grayscale values to enhance fringe quality when the projector is not perfectly in focus. With this novel technique, we will show that the phase error is approximately 1/3 of the square binary method when fringe pattern is dense and the projector is nearly focused.