X-ray phase contrast imaging holds great promise for improving the visibility of light-element materials such as soft tissues and tumors. The single-mask differential phase contrast imaging method stands out as a simple and effective approach to yield differential phase contrast. In this work, we introduce a model for a single-mask phase imaging system based on the transport-of-intensity equation. Our model provides an accessible understanding of signal and contrast formation in single-mask x-ray phase imaging, offering a clear perspective on the image formation process, for example, the origin of alternate bright and dark fringes in phase contrast intensity images. Aided by our model, we present an efficient retrieval method that yields differential phase contrast imagery in a single acquisition step. Our model gives insight into the contrast generation and its dependence on the system geometry and imaging parameters in both the initial intensity image as well as retrieved images. The model validity as well as the proposed retrieval method are demonstrated via both experimental results on a system developed in house as well as Monte Carlo simulations. In conclusion, our work not only provides a model for an intuitive visualization of image formation but also offers a method to optimize differential phase imaging setups, holding tremendous promise for advancing medical diagnostics and other applications.

中文翻译：

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单掩模 X 射线微分相衬成像的强度传输模型

X 射线相衬成像在提高软组织和肿瘤等轻元素材料的可见度方面具有广阔的前景。单掩模微分相衬成像方法是一种简单有效的产生微分相衬的方法。在这项工作中，我们介绍了一种基于强度传输方程的单掩模相位成像系统模型。我们的模型提供了对单掩模 X 射线相位成像中信号和对比度形成的简单理解，为图像形成过程提供了清晰的视角，例如，相位对比度强度图像中亮暗条纹交替的起源。在我们的模型的帮助下，我们提出了一种有效的检索方法，可以在单个采集步骤中产生微分相差图像。我们的模型深入了解了对比度的生成及其对初始强度图像和检索图像中的系统几何形状和成像参数的依赖性。通过内部开发的系统的实验结果以及蒙特卡罗模拟证明了模型的有效性以及所提出的检索方法。总之，我们的工作不仅提供了图像形成直观可视化的模型，而且还提供了优化微分相位成像设置的方法，为推进医疗诊断和其他应用带来了巨大的希望。