论文标题

重叠的域分解方法用于Ptychographic成像

Overlapping Domain Decomposition Methods for Ptychographic Imaging

论文作者

Chang, Huibin, Glowinski, Roland, Marchesini, Stefano, Tai, Xue-cheng, Wang, Yang, Zeng, Tieyong

论文摘要

在Ptychography实验中,通常需要冗余扫描以确保稳定的恢复,从而产生大量帧,因此它对并行计算的需求构成了巨大的需求,以解决这个大规模的反问题。在本文中,我们提出了重叠的域分解方法(DDMS),以解决ptychographic成像中的非凸优化问题。他们将整个域上定义的问题解散为仅在子域上定义的子问题,这些问题在这些子域的重叠区域中具有同步信息,从而导致高负载平衡的高度平行算法。更具体地说,对于非盲恢复(提前已知的探针),通过实施图像重叠区域的连续性(样品),基于新型的平滑幅度扭曲高斯度量度量(ST-AGM)建立了非线性优化模型。这样的度量标准允许用封闭形式快速计算近端映射,同时,由于其Lipschitz的平滑度,因此提供了一阶非convex优化算法的收敛保证。然后,利用乘数的交替方向方法(ADMM)来生成有效的重叠域分解基于二级域域分解(DD)的基于基于PTYCOMAGH算法(OD2P),其中所有子都可以用近距离溶液来计算所有子问题。在轻度条件下得出。此外,它已扩展到更一般的情况,包括多重辅助DD和盲目恢复。进一步进行了数值实验,以显示提出的算法的性能,证明了对噪声的良好收敛速度和稳健性。

In ptychography experiments, redundant scanning is usually required to guarantee the stable recovery, such that a huge amount of frames are generated, and thus it poses a great demand of parallel computing in order to solve this large-scale inverse problem. In this paper, we propose the overlapping Domain Decomposition Methods(DDMs) to solve the nonconvex optimization problem in ptychographic imaging. They decouple the problem defined on the whole domain into subproblems only defined on the subdomains with synchronizing information in the overlapping regions of these subdomains,thus leading to highly parallel algorithms with good load balance. More specifically, for the nonblind recovery (with known probe in advance), by enforcing the continuity of the overlapping regions for the image (sample), the nonlinear optimization model is established based on a novel smooth-truncated amplitude-Gaussian metric (ST-AGM). Such metric allows for fast calculation of the proximal mapping with closed form, and meanwhile provides the possibility for the convergence guarantee of the first-order nonconvex optimization algorithm due to its Lipschitz smoothness. Then the Alternating Direction Method of Multipliers (ADMM) is utilized to generate an efficient Overlapping Domain Decomposition based Ptychography algorithm(OD2P) for the two-subdomain domain decomposition (DD), where all subproblems can be computed with close-form solutions.Due to the Lipschitz continuity for the gradient of the objective function with ST-AGM, the convergence of the proposed OD2P is derived under mild conditions. Moreover, it is extended to more general case including multiple-subdomain DD and blind recovery. Numerical experiments are further conducted to show the performance of proposed algorithms, demonstrating good convergence speed and robustness to the noise.

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