Kumar Gautam Surya, Singh Rakesh Kumar, Narayanamurthy C S, Naik Dinesh N
J Opt Soc Am A Opt Image Sci Vis. 2020 Nov 1;37(11):1826-1831. doi: 10.1364/JOSAA.402731.
A phase-retrieval algorithm can reconstruct the phase of an object from an intensity image of a diffraction pattern recorded at the Fourier plane, provided one makes a right initial guess. For the algorithms that are based on an initial random guess, at times, the output either becomes nondeterministic, becomes nonconvergent, or develops a twin image. For improving the performance of the algorithms by eliminating the twin image and for bringing uniqueness to the output, prior information about the object or more intensity measurements are needed. In order to achieve this using only a single acquisition of the intensity pattern recorded at the Fourier plane for an object, we propose a method in which object support, along with the object information in the case in which the object has a direction of asymmetry, can be measured from the object autocorrelation and utilized as an initial guess in the phase-retrieval algorithm. In the process, we explore how even a partial asymmetry in the object distribution can lead to a good solution in the phase-retrieval algorithm. This method is beneficial for unique phase detection without any twin artifact in various fields of optics. We theoretically analyze the proposed method and validate it by carrying out the simulations and experiment.
相位恢复算法可以从在傅里叶平面记录的衍射图案的强度图像中重建物体的相位，前提是做出正确的初始猜测。对于基于初始随机猜测的算法，有时输出要么变得不确定，要么不收敛，要么出现孪生像。为了通过消除孪生像来提高算法的性能并使输出具有唯一性，需要有关物体的先验信息或更多的强度测量值。为了仅通过对物体在傅里叶平面记录的强度图案进行一次采集来实现这一点，我们提出了一种方法，在该方法中，可以从物体自相关测量物体支撑以及物体具有不对称方向情况下的物体信息，并将其用作相位恢复算法的初始猜测。在此过程中，我们探索即使物体分布中的部分不对称性如何也能在相位恢复算法中导致良好的解决方案。该方法有利于在光学的各个领域中进行无任何孪生伪影的唯一相位检测。我们对所提出的方法进行了理论分析，并通过进行模拟和实验对其进行了验证。
