摘要:
系统研究了两步相移数字全息干涉术中相移误差引起的波前再现误差的计算和校正方法.基于衍射物光相位分布的随机性和振幅相位的相互独立性原理,介绍了相移数字全息中物光波前再现误差的表达形式,推导出步长为π/2的两步算法中物光重建误差的表达式.通过进一步分析这一重建误差的结构和特点,结合物光表达式,给出了自动校正相移误差引起的波前重建误差的校正方法.该方法无需增加测量,在未知相移误差大小的情况下,只对标准两步相移算法恢复的物光复振幅进行处理就可以实现对物光振幅和相位的同时校正.计算机模拟结果表明,校正后可将物光重建误差减小两个数量级.光学实验也令人满意地验证了该方法的有效性和高效性.
Abstract:
The method of calculating and correcting object wave reconstruction errors caused by phase shift errors in two-step phase-shifting interferometry is studied systematically.Based on the principle of random distribution and the amplitude-phase independence of diffractive object wave,the expression of objective wave reconstruction error is introduced and the formula for that in the two-step standard algorithm is deduced.The automatic error correction method is suggested by further analyzing the structures,the characters of those errors caused by phase shift errors,and the objective expression.By the proposed method,the reconstructive amplitude and phase errors can be corrected at the same time through simple operation on the objective complex amplitude reconstructed by the standard two-step method without the additional measurement or the acknowledge of phase shift.The computer simulations are carried out to verify the effectiveness of this method,and the results show that the method is robust and reduces the effect of phase shift error on object wave-front reconstruction by about 2 orders of magnitude.Optical experiments also indicate that this method is effective and efficient.
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