A single‐shot 3d measuring method based on quadrature phase‐shifting color composite grating projection

Abstract

A single‐shot three‐dimensional measuring method based on quadrature phase‐shifting color composite grating projection is proposed. Firstly, three quadrature phase‐shifting sinusoidal gratings are encoded in red (R), green (G), and blue (B) channels respectively, composed singleframe color composite grating. This color composite grating is projecting obliquely on the object by DLP. After that, the color camera which is placed in a specific location is used to capture the corresponding color deformed pattern and send it to the PC. Then, by color separation, the color deformed pattern is demodulated as the corresponding three‐frame monochromatic deformed patterns with a shifted quadrature phase. Due to the existences of sensitivity differences and color crosstalk among the tricolor channels, we propose a gray imbalance correction method based on the DC component’s consistency approximation. By the established 3D reconstruction physical model, the measurement of 3D shape can be achieved. Many experimental results for static and moving objects prove the proposed method’s feasibility and practicability. Owing to the single‐shot feature of the proposed method, it has a good application prospect in real‐time and high‐speed 3D measurement.