单透镜系统中与色散融合的混合相位恢复方法

Hybrid phase retrieval with chromatic dispersion in single-lens system

相位恢复是利用能观测到的强度信息恢复原始相位信息。强度传输方程(TIE)作为一种传统的非干涉相位恢复技术,只需通过测量至少两个相近平面的强度信息即可计算出相位信息。这种方法通常需要通过移动被测物体或摄像机来获取强度图像,不可避免地会产生机械误差。提出了一种新的相位恢复方法:与色散融合的混合相位恢复算法(CD-HPR)。通过设置不同波长的光通过单透镜系统得到物体在同一位置成的像,这样不需要机械运动就能获得聚焦和散焦图像强度,然后结合散焦量与波长之间的关系计算出散焦量,再用强度传输方程计算初始相位信息。角谱迭代算法的使用较好地改进了初始相位值。在仿真实验中,该方法恢复的相位与原始相位之间的均方差为0.1076;同时,通过实验恢复了透镜阵列的相位,实验结果与实际参数的误差为3.4%,证明了该方法的正确性和有效性。该方法扩展了传统方法要求光源为单色的局限性,提高了计算精度。

Phase retrieval is to recover the original phase information by using the intensity information obtained from observation. Transport of intensity equation(TIE), as a traditional non-interference phase retrieval technique, can compute the losing phase information from only a minimum of two intensity measurements at closely spaced planes by solving the equation. This method usually requires the acquisition of intensity images by moving the object to be tested or CCD, which inevitably results in mechanical errors. A new phase retrieval method called chromatic dispersion-hybrid phase retrieval(CD-HPR) was proposed. The object was imaged at the same position by setting different wavelengths of light after passing through the single-lens system, in-focus and defocus intensity images were obtained without mechanical movement, and the initial phase information of an object was calculated from the phase retrieval technique based on TIE by combining the relationship between the defocus amount and the wavelength. Next angular spectrum iteration was used to improve the initial phase information. In this simulation, the RMSE between the phase recovered by this method and the original phase was 0.1076. At the same time, the phase of the lens array was restored by experiment. The error between the experimental result and the real parameter is 3.4%, which proves the correctness and effectiveness of the proposed method. This method extends the limitation of the traditional method that requires the light source to be monochromatic and improves the calculation accuracy.