基于二进制条纹加相位编码条纹离焦投影的三维测量方法

复杂表面的精密三维测量在工业无损检测中非常重要。二进制条纹离焦投影方法在快速三维测量中有重要的应用前景，但该方法难以实现复杂表面高精度三维测量。为此，提出了基于二进制条纹加相位编码条纹离焦投影的三维测量方法。由于离焦投影滤除了高次谐波和高频噪声，可以克服投影仪的非线性伽马效应，与传统投影正弦条纹方法相比，提高了其测量精度。针对离焦投影时，随着相位编码条纹频率增大，条纹级次判决困难，出现周期错位，导致相位解包裹出错，提出了相移编码方法来解决以上问题。采用相移编码方法校正周期错位，使条纹级次判决准确，进一步提高其测量精度。实验结果表明，其测量精度可以达到0.044 mm，验证了本方法的有效性和实用性。

3D measurement method based on binary fringe plusphase coding fringe defocus projection

Precision three-dimensional measurement of complex surface is very significant in industrial non-destructive testing. The method of binary fringe defocus projection has important application prospects in fast three-dimensional measurement; however, it is difficult to realize high precision three-dimensional measurement on complex surface.For this reason, a complex surface 3D measurement method based on binary fringe plus phase coding fringe defocus projection is proposed. Because of defocus, the high harmonics and high-frequency noise are filtered out, the nonlinear Gamma effect of the projector can be overcome, its measurement accuracy can be improved, compared with the traditional projection sinusoidal fringe method. For the out-of-focus projection, as the frequency of the phase coding fringe increases, the fringe order decision becomes difficult, the periodic dislocation occurs which can lead to the errors of phase unwrapping.In order to solve the problem, the principle of phase-shift coding method is proposed to correct the periodic dislocation and make the fringe order decision accurate, so the measurement accuracy is further improved. The experimental results show that the accuracy of this method can reach 0.044 mm, which verifies the validity and practicability of the method.