Three-dimensional shape profiling by projection of binary patterns: generated by a deterministic optimization approach

Three-dimensional shape profiling by sinusoidal phase-shifting methods is affected by the non-linearity of the projector. To overcome this problem, the defocused projection of binary patterns has become an important alternative to generate sinusoidal fringe patterns. In this paper, we present an efficient technique to generate binary fringe patterns where we use the symmetry and periodicity properties of binary-coded sinusoidal intensity. This reduces the search-space for the optimization problem. The patterns are projected out-of-focus to generate quasi-sinusoidal patterns, which can be used together with a phase-shifting algorithm to retrieve 3-D shape measurements. Simulations and experimental results show the feasibility of the proposed scheme.