实现无重叠单次曝光相干成像，提升同步辐射与X射线自由电子激光效率
Towards single-shot coherent imaging via overlap-free ptychography
- 用可调坐标分组替代硬性重叠要求，结合可微正向模型与泊松光子计数似然
- 单次曝光重建在实验探针下达到SSIM 0.904，仅需10^4光子/帧，接近重叠约束结果
- 支持未见照明条件泛化，每GPU吞吐量达传统方法40倍，适合高通量光源成像
同步辐射与X射线自由电子激光中的相位扫描成像需密集重叠扫描，限制通量并增加剂量。将相干衍射成像扩展至大尺度样本的无重叠单次曝光仍为开放问题。本文拓展PtychoPINN框架，实现菲涅尔相干衍射成像几何下的无重叠、单次曝光重建，同时加速传统多帧相位扫描。该方法将可微正向散射模型与泊松光子计数似然结合，真实空间重叠作为可调参数通过基于坐标的分组实现，而非强制要求。合成基准测试显示，低光子数（约10^4光子/帧）下重建仍准确；实验探针下无重叠单次重建的振幅结构相似性（SSIM）达0.904，优于重叠约束重建的0.968。相较同架构监督模型（16,384张训练图），仅用1,024张图像即达更高SSIM，并泛化至未见照明条件。每GPU吞吐量约为最小二乘最大似然（LSQ-ML）方法的40倍（128×128分辨率匹配）。实验数据经阿贡国家实验室和直线加速器相干光源验证，统一了单曝光菲涅尔CDI与重叠相位扫描，支持现代光源下的低剂量、高通量成像。
原文摘要 · Abstract (English)
Ptychographic imaging at synchrotron and XFEL sources requires dense overlapping scans, limiting throughput and increasing dose. Extending coherent diffractive imaging to overlap-free operation on extended samples remains an open problem. Here, we extend PtychoPINN (O. Hoidn \emph{et al.}, \emph{Scientific Reports} \textbf{13}, 22789, 2023) to deliver \emph{overlap-free, single-shot} reconstructions in a Fresnel coherent diffraction imaging (CDI) geometry while also accelerating conventional multi-shot ptychography. The framework couples a differentiable forward model of coherent scattering with a Poisson photon-counting likelihood; real-space overlap enters as a tunable parameter via coordinate-based grouping rather than a hard requirement. On synthetic benchmarks, reconstructions remain accurate at low counts ($\sim\!10^4$ photons/frame), and overlap-free single-shot reconstruction with an experimental probe reaches amplitude structural similarity (SSIM) 0.904, compared with 0.968 for overlap-constrained reconstruction. Against a data-saturated supervised model with the same backbone (16,384 training images), PtychoPINN achieves higher SSIM with only 1,024 images and generalizes to unseen illumination profiles. Per-graphics processing unit (GPU) throughput is approximately $40\times$ that of least-squares maximum-likelihood (LSQ-ML) reconstruction at matched $128\times128$ resolution. These results, validated on experimental data from the Advanced Photon Source and the Linac Coherent Light Source, unify single-exposure Fresnel CDI and overlapped ptychography within one framework, supporting dose-efficient, high-throughput imaging at modern light sources.
Thank you to arXiv for use of its open access interoperability. PaperDance 不是 arXiv 官方产品；中文卡片由大模型生成，请以原文为准。