Optimized dithering technique for three-dimensional shape measurement with projector defocusing

There have been active studies on optimized dithering techniques to improve 3D shape measurement quality with image sensor and defocusing projector. These techniques can be classified into intensity-based optimization technology and phase-based optimization technology. However, those phase-based optimization methods are sensitive to the amount of defocusing while intensity-based optimization methods cannot reduce phase errors efficiently. This paper presents an optimization framework. This framework combines structural similarity index measurement and intensity residual error optimization. By applying this optimization framework to patches and tiling the best patch, high quality fringe pattern can be generated for three-dimensional measurement. Both simulation and experimental results show that this proposed algorithm can achieve phase quality improvements and it is robust to various defocusing levels.