In situ X-ray beam imaging using an off-axis magnifying coded aperture camera system.
In situ X-ray beam imaging using an off-axis magnifying coded aperture camera system.
复制标题
DOI：
10.1107/s0909049513011060
复制
发表时间：
2013-07
影响因子：
2.5
通讯作者：
van Silfhout R
中科院分区：
文献类型：
--
作者：
Kachatkou A;Kyele N;Scott P;van Silfhout R
本文提出了一种成像模型和重建算法，用于从基于编码孔径相机的X射线束监视器记录的数据中获得X射线束横截面图像，所述编码孔径相机收集从以倾斜角度放置在X射线束中的薄箔散射的辐射。提出了一种透明X射线束成像与位置测量系统的成像模型和图像重建算法。该仪器依赖于编码孔径相机来记录入射光束在以倾斜角度放置在光束中的薄箔上的足迹的放大图像。成像模型将仪器表示为线性系统，其脉冲响应考虑了由于箔片的有限厚度、相机孔径的形状和大小以及探测器的点扩散函数而引起的图像模糊。图像重建算法首先使用建模的脉冲响应函数去除图像模糊，然后校正由箔倾斜引起的几何失真。在同步辐射光束线上对该算法进行了实验验证。结果表明，所提出的成像系统产生的X射线束横截面的图像具有与使用暴露于直接束的X射线相机获得的图像相当的质量。
This paper presents an imaging model and a reconstruction algorithm for obtaining X-ray beam cross-sectional images from the data recorded by an X-ray beam monitor based on a coded aperture camera that collects radiation scattered from a thin foil placed in the X-ray beam at an oblique angle. An imaging model and an image reconstruction algorithm for a transparent X-ray beam imaging and position measuring instrument are presented. The instrument relies on a coded aperture camera to record magnified images of the footprint of the incident beam on a thin foil placed in the beam at an oblique angle. The imaging model represents the instrument as a linear system whose impulse response takes into account the image blur owing to the finite thickness of the foil, the shape and size of camera’s aperture and detector’s point-spread function. The image reconstruction algorithm first removes the image blur using the modelled impulse response function and then corrects for geometrical distortions caused by the foil tilt. The performance of the image reconstruction algorithm was tested in experiments at synchrotron radiation beamlines. The results show that the proposed imaging system produces images of the X-ray beam cross section with a quality comparable with images obtained using X-ray cameras that are exposed to the direct beam.