arXiv:2608.24806physics.opticseess.IV2026-08

对比两种算法在噪声和模糊下的表现,为低剂量X射线成像提供选型依据。

Effects of Quantum Noise and Source Blurring on Dark-Field Signal Retrieval in X-ray Speckle-Based Imaging

论文配图:Effects of Quantum Noise and Source Blurring on Dark-Field Signal Retrieval in X-ray Speckle-Based Imaging
图 1 · 摘自论文原文
  • 对比差分法(LCS)与局部块匹配法(XST-XSVT)的抗噪能力
  • 在光子匮乏时,LCS信号线性度骤降,而XST-XSVT保持稳定
  • 适合低剂量、低相干光源的临床前与临床应用系统设计

X射线斑点基暗场成像对亚像素结构特征具有高灵敏度,但其在临床和临床前应用中的定量可靠性受制于低光子通量和有限焦斑尺寸。然而,硬件引入的噪声和源模糊如何通过重建算法影响信号完整性仍不明确。本文系统评估了两种数学上不同的框架——基于差分的内在追踪(低相干系统,LCS)和基于局部块的显式追踪(X射线斑点追踪-斑点向量追踪,XST-XSVT)在光子匮乏和源模糊条件下的算法鲁棒性,以信号线性度、灵敏度和偏差为指标。实验表明,输入斑点图失真会因算法架构不同而以截然不同的方式传播:在严重光子匮乏下,LCS因导数噪声放大导致信号线性度和灵敏度急剧下降,基线偏差显著升高;而XST-XSVT通过局部方差计算天然抑制随机噪声,有效控制灵敏度损失并维持稳定基线。在模糊受限条件下,源模糊使斑点图案模糊,直接降低两种方法的暗场灵敏度。该研究明确了低功率与低相干X射线系统的操作边界,指导算法选择与框架优化,推动定量暗场成像在临床前及临床应用中的实现。

原文摘要 · Abstract (English)

X-ray speckle-based dark-field imaging offers high sensitivity to sub-pixel structural features, yet its quantitative reliability in clinical and preclinical settings remains constrained by low photon flux and finite focal spot sizes. However, how hardware-induced noise and source blurring propagate through retrieval algorithms to degrade signal integrity is not fully understood. Here, we systematically evaluate algorithm robustness quantified by signal linearity, sensitivity, and bias under photon starvation and source blurring across two mathematically distinct frameworks: differential-based intrinsic tracking (Low-Coherence System, LCS) and patch-wise explicit tracking (X-ray Speckle-Tracking Speckle-Vector-Tracking, XST-XSVT). Our experimental results demonstrate that input speckle pattern distortions propagate through retrieval algorithms in fundamentally different ways depending on algorithm architecture. As an example, using our setup, under severe photon starvation, derivative noise amplification in LCS causes its dark-field signal linearity and sensitivity to drop precipitously, while sharply elevating baseline bias. In contrast, XST-XSVT restricts these losses for sensitivity while maintaining a stable baseline, as its patch-wise variance calculation inherently suppresses stochastic noise. Similarly, under blur-limited conditions , source blurring washes out the speckle pattern, directly reducing dark-field sensitivity for both LCS and XST-XSVT. This characterization establishes operational boundaries for low-power and low-coherence X-ray systems, guiding algorithm selection and framework optimization to realize quantitative dark-field imaging in preclinical and clinical applications.

X射线成像暗场成像噪声抑制低剂量

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