Subpixel correction of diffraction pattern shifts in ptychography via automatic differentiation

Fuente: arXiv
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Autores principales: Xu, Zhengkang, Chen, Yanqi, Xu, Hao, Wang, Qingxin, Niu, Jin, Huang, Lei, Tang, Jiyue, Ma, Yongjun, Wang, Yutong, Shi, Yishi, Ke, Changjun, Li, Jie, Fan, Zhongwei
Formato: Preprint
Publicado: 2025
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author Xu, Zhengkang
Chen, Yanqi
Xu, Hao
Wang, Qingxin
Niu, Jin
Huang, Lei
Tang, Jiyue
Ma, Yongjun
Wang, Yutong
Shi, Yishi
Ke, Changjun
Li, Jie
Fan, Zhongwei
author_facet Xu, Zhengkang
Chen, Yanqi
Xu, Hao
Wang, Qingxin
Niu, Jin
Huang, Lei
Tang, Jiyue
Ma, Yongjun
Wang, Yutong
Shi, Yishi
Ke, Changjun
Li, Jie
Fan, Zhongwei
contents Ptychography, a coherent diffraction imaging technique, has become an indispensable tool in materials characterization, biological imaging, and nanostructure analysis due to its capability for high-resolution, lensless reconstruction of complex-valued images. In typical workflows, raw diffraction patterns are commonly cropped to isolate the valid central region before reconstruction. However, if the crop is misaligned from the diffraction pattern's zero-order, reconstruction may suffer from slower convergence, phase wrapping, and reduced image fidelity. These issues are further exacerbated in experimental configurations involving reflective geometries or broadband illumination, where incorrect cropping introduces systematic preprocessing errors that compromise the entire ptychographic inversion. To address this challenge, we present an approach based on automatic differentiation (AD), where the cropping shift is treated as an optimizable parameter within the reconstruction framework. By integrating shift correction into the backpropagation loop, our method simultaneously refines the object, probe, and shift positions without requiring manual tuning. Simulation results demonstrate that, even with initial offsets ranging up to 5 pixels, the proposed method achieves subpixel correction, with an average deviation below 0.5 pixels. Experiments in the extreme ultraviolet (EUV) regime further validate the method's robustness and effectiveness. This AD-based strategy enhances the automation and robustness of ptychographic reconstructions, and is adaptable to diverse experimental conditions.
format Preprint
id arxiv_https___arxiv_org_abs_2507_03640
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Subpixel correction of diffraction pattern shifts in ptychography via automatic differentiation
Xu, Zhengkang
Chen, Yanqi
Xu, Hao
Wang, Qingxin
Niu, Jin
Huang, Lei
Tang, Jiyue
Ma, Yongjun
Wang, Yutong
Shi, Yishi
Ke, Changjun
Li, Jie
Fan, Zhongwei
Optics
Image and Video Processing
Ptychography, a coherent diffraction imaging technique, has become an indispensable tool in materials characterization, biological imaging, and nanostructure analysis due to its capability for high-resolution, lensless reconstruction of complex-valued images. In typical workflows, raw diffraction patterns are commonly cropped to isolate the valid central region before reconstruction. However, if the crop is misaligned from the diffraction pattern's zero-order, reconstruction may suffer from slower convergence, phase wrapping, and reduced image fidelity. These issues are further exacerbated in experimental configurations involving reflective geometries or broadband illumination, where incorrect cropping introduces systematic preprocessing errors that compromise the entire ptychographic inversion. To address this challenge, we present an approach based on automatic differentiation (AD), where the cropping shift is treated as an optimizable parameter within the reconstruction framework. By integrating shift correction into the backpropagation loop, our method simultaneously refines the object, probe, and shift positions without requiring manual tuning. Simulation results demonstrate that, even with initial offsets ranging up to 5 pixels, the proposed method achieves subpixel correction, with an average deviation below 0.5 pixels. Experiments in the extreme ultraviolet (EUV) regime further validate the method's robustness and effectiveness. This AD-based strategy enhances the automation and robustness of ptychographic reconstructions, and is adaptable to diverse experimental conditions.
title Subpixel correction of diffraction pattern shifts in ptychography via automatic differentiation
topic Optics
Image and Video Processing
url https://arxiv.org/abs/2507.03640