为了解决空间载波相移(SCPS)法中载波频率不确定引入的误差,提出了一种基于最小二乘迭代的空间载波相移算法。先将单幅随机空间载波频率干涉图转化成四幅随机相移量的时域干涉图,然后用最小二乘迭代求得相位信息。模拟计算和实验结果表明,该算法只需10次左右的迭代计算就可实现算法峰值(PV)精度优于λ/20,均方根(RMS)精度优于λ/200,高于快速傅里叶变换(FFT)法; 通过提高空间载波频率,使载波方向接近45°或135°可提高该算法的精度。

An advanced spatial-carrier phase-shifting (SCPS) algorithm based on least-squares iterative procedure is proposed to cope with the errors caused by the uncertainty of spatial carrier frequency. The algorithm divides the randomly spatial carrier interferogram into four randomly phase-shifted interferograms and then obtains the phase distributions by a least-squares iterative procedure. The algorithm provides stable and fast convergence, high spatial frequency resolution and accurate phase extraction with only one single randomly spatial carrier interferogram. The results of computer simulation and experiment show that the accuracy is better than λ/20 (peak value, PV) and λ/200 (root mean square, RMS) with about 10 times iterations and it is better than that obtained by the fast Fourier transform (FFT) algorithm. Computer simulations also show that the accuracy of the algorithm can be improved by increasing the spatial carrier frequency and making the direction of the carrier near 45° or 135°.