A real-time three-dimensional(3D) shape measuring method based on dual-frequency spatial phase-shifting measuring profilometry (SPSMP) is proposed. To combine the low-frequency and high-frequency gratings into one single composite pattern, each individual grating is modulated along orthogonal direction with a distinct carrier frequency. Since the spectrum components are staggered in the spectrum of the composite deformed pattern, the low-frequency and high-frequency deformed patterns with background light can be demodulated easily. Then two groups of spatial phase-shifting deformed sub-patterns are extracted from the corresponding deformed patterns to calculate the low-frequency wrapped phase and the high-frequency wrapped phase. According to the dual-frequency phase unwrapping algorithm, the high-frequency wrapped phase is guided by the low-frequency unwrapped phase. Compared to the existing multi-frequency single-shot fringe projection, the filtering process of the proposed method is more concise, it does not involve multiple filtering and the extraction of the single spectrum component. The static and real-time experimental results show that the proposed method inherits the high accuracy of PMP, while guaranteeing single-shot feature.

提出了一种基于双频空间相移测量轮廓图（SPSMP）的实时三维形状测量方法。为了将低频和高频光栅组合成一个单一的合成图案，每个单独的光栅都以正交的方向以不同的载波频率进行调制。由于光谱成分在复合变形图案的光谱中错开，因此可以容易地解调具有背景光的低频和高频变形图案。然后从相应的变形图案中提取出两组空间相移变形子图案，以计算低频包裹相位和高频包裹相位。根据双频相位展开算法，高频包裹相位由低频未包裹相位引导。与现有的多频单发条纹投影相比，该方法的滤波过程更加简洁，不涉及多次滤波和单频谱分量的提取。静态和实时实验结果表明，该方法在保证单发特性的同时，继承了PMP的高精度。