为了实现不同颜色、不同光照条件下物体的高精度三维测量，对多频率三维测量中的相位叠加、相位编码以及全局解相方法进行了研究。首先，选取三种不同频率的正弦波形，经过 3~8步相移，向物体投射光信息，并通过相位叠加，获得等效频率的相位信息。接着，利用已经获得的等效相位信息，对三种不同频率的相位信息进行编码。然后，在相位编码的基础之上，通过全局解相方法，获得全局相位信息，进而获得高精度物体三维坐标。最后，介绍了精度验证方法及其与传统格雷码三维测量方法的精度对比。实验结果表明: 格雷码的三维测量精度为±0.04 mm；多频率三维测量精度为 ±0.02 mm。多频率方法不但测量精度高，并且可以弥补格雷码方法无法实现不同光照条件下的三维测量难题，具有更广泛的适用性。

In order to realize the high precision 3D measurement for the objects with different color under different illumination, the phase composition, phase coding and global phase unwrapping methods are researched. First, three different frequency sinusoidal waveforms are selected to be projected to the object after 3~8 phase shift. The equivalent frequency is acquired by the phase composition. The phase coding according to the three different frequencies is performed based on the equivalent frequency. Through the global phase unwrapping method, the global phase can be acquired, further to compute the high precision 3D coordinate. The precision testing method and comparison between the proposed method and the Gray Code method are introduced at last. Experimental results indicate that the precision of the Gray Code method is 0.04 mm; and the precision of the proposed method is 0.02 mm. The proposed method is high precision and better than the Gray Code method because it can solve the problem of the objects under different illumination.