3D shape measurement based on the novel non- aligned phase-coding method

As a kind of three-dimensional(3-D) shape measurement technology, the phase-coding method was widely used because of its high robustness. However, due to the interference of nonlinear and noise, error may appear in the edge of the fringe, which leads to 2π phase jump errors in the unwrapped phase map. To alleviate this problem, a new method based on non-aligned phase-coding was proposed, in which the phase difference of sinusoidal fringe patterns and fringe order patterns is a fixed value. Before the wrapped phase is unwrapped, the fringe order is re-corrected by the wrapped phase to make them aligned. Since the wrapped phase and the corrected fringe order are strictly aligned, the errors are eliminated. Finally, several groups of comparative experiments are carried out to demonstrate the robustness and effectiveness of the proposed method.