标题： 研究迭代ptychography在原子分辨率低剂量成像中的收敛特性 显示英文标题

标题： Investigating the convergence properties of iterative ptychography for atomic-resolution low-dose imaging

摘要： 本研究调查了在低电子剂量（$<$10$^3$$e^-/A^2$）下一组迭代电子ptychography方法的收敛特性，并特别关注用户定义的更新强度的影响。 我们证明，对于该参数选择适当的值，理想情况下小于文献中通常使用的值，对于实现投影静电势的准确重建至关重要。 使用一个薄层混合有机-无机甲脒铅溴化物（FAPbBr$_{3}$）样品的4D数据集，我们表明，只有当物体和探针的更新强度相对于文献中找到的值较小时，实际收敛才是可行的。 此外，我们证明在低电子剂量下，当更新强度系数降低到某个阈值以下时，重建初始误差会增加，这强调了临界值的存在，超过这些值后算法会陷入局部最小值。 这些发现突显了在迭代ptychography中仔细优化重建参数的必要性，尤其是在使用低电子剂量时，以确保结果的有效收敛和正确性。 显示英文摘要

摘要： This study investigates the convergence properties of a collection of iterative electron ptychography methods, under low electron doses ($<$ 10$^3$ $e^-/A^2$) and gives particular attention to the impact of the user-defined update strengths. We demonstrate that carefully chosen values for this parameter, ideally smaller than those conventionally met in the literature, are essential for achieving accurate reconstructions of the projected electrostatic potential. Using a 4D dataset of a thin hybrid organic-inorganic formamidinium lead bromide (FAPbBr$_{3}$) sample, we show that convergence is in practice achievable only when the update strengths for both the object and probe are relatively small compared to what is found in literature. Additionally we demonstrate that under low electron doses, the reconstructions initial error increases when the update strength coefficients are reduced below a certain threshold emphasizing the existence of critical values beyond which the algorithms are trapped in local minima. These findings highlight the need for carefully optimized reconstruction parameters in iterative ptychography, especially when working with low electron doses, ensuring both effective convergence and correctness of the result.