Improved intensity-optimized dithering technique for 3D shape measurement

•A novel objective function was proposed to generate high quality binary patterns.•A new framework, optimizing pixels of a pattern group by group, was proposed.•The square binary patterns can obtain better phase quality for Narrow fringe stripes.

The recently proposed optimized dithering techniques are able to improve measurement quality obviously. However, those phase-based optimization methods are sensitive to the amount of defocusing while intensity-based optimization methods cannot reduce the phase error efficiently. This paper presents a novel method, minimizing a proposed objective function named intensity residual error (IRE), as well as a novel framework, optimizing pixels group by group, to construct binary patterns for high-quality 3D shape measurement. Both the simulation and experimental results show that this proposed algorithm can achieve phase quality improvements over other recently optimized dithering techniques with various amounts of defocusing.