数字全息相位再现误差分析及抑制技术

为实现基于数字全息的三维轮廓测量，本文探讨了菲涅耳近似算法实现数字全息相位再现的误差及抑制技术。首先理论分析了基于菲涅耳近似算法实现全息相位再现所包含的误差项，然后计算机模拟了数字离轴全息图的记录和相位再现结果，在此基础，模拟分析了离焦误差、数字再现光波误差及样本深度对相位再现的影响。针对记录参考光波和光学器件所引入的相位误差及其不定性，本文提出利用相位相减全息图处理方法加以消除，并给出了实验结果加以验证。模拟分析结果表明，菲涅耳近似算法误差、离焦误差、数字再现光波倾斜误差、解包裹错误对相位再现结果都有不同程度的影响。若获得高精度的再现结果，对记录过程、再现参数选择和处理方法都要进行严格控制或适当的选取。

Aberration and its reduction of Phase reconstructed via digital holography

In order to realize three dimensional structure measurement by digital holography, the aberration and its reduction of the phase reconstructed based on Fresnel approximation algorithm are discussed. First, total aberrations of phase reconstructed based on Fresnel approximation algorithm are analyzed, then the digital recording and numerical reconstruction of hologram of phase grating are simulated by computer. Further, the influence from the defocus, the aberration of digital reconstruction light and the depth of the tested samples on the phase reconstructed is simulated and analyzed. It presents the phase subtraction of hologram method to eliminate the phase aberration from the recording light wave and optical parts. Because this aberration has ambiquity characteristic, the experimental results are provided to validate this method. Simulation results indicate that the error from Fresnel approximation arithmetic, the defocus aberration, the digital reconstruction light wave and the wrong unwrapped processing will effect the phase to be reconstructed rightly. High precision phase reconstructed can be gotten when the recording process, reconstruction parameters and the reconstruction method are controlled strictly and selected properly.