Abstract:The complementary Gray code double N-step phase-shifting method has become a research hotspot in the field of fringe projection profilometry because of its good robustness and high detection accuracy. However, the traditional complementary Gray code double N-step phase-shifting method has the problems of low detection efficiency and does not eliminate the periodic spurious tones phase error. To solve these problems, the traditional complementary Gray code double N-step phase-shifting method is improved to eliminate periodic spurious tones phase errors in this paper. Firstly, the deformed fringe images are captured by camera to calculate two groups of wrapped phases. Next, the correlation of the two groups of wrapped phases is used to eliminate the phase difference and periodic spurious tones phase error in the detection data, and the two groups of wrapped phases are fused. Finally, the fused wrapped phase is unwrapped by the complementary Gray code phase unwrapping method. The experimental results show that the method in this paper could effectively eliminate the periodic spurious tones phase error and obtain the high-precision unwrapped phase, compared to the complementary Gray code double N-step phase-shifting method that does not eliminate periodic spurious tones phase errors, the accuracy of the detection method in this paper has been improved by about 24. 57% . Compared with the complementary Gray code N-step phase-shifting method, the accuracy of the detection method in this paper has been improved by about 6. 29% . Keywords:double N-step phase shift method; wrapped phase; periodic spurious tones ph