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X射线衍射增强相衬成像相位信息提取方法研究 总被引:2,自引:0,他引:2
基于同步辐射的X射线衍射增强相衬成像有效地应用于低吸收轻物质(例如软组织)材料的内部结构检查,其关键技术是如何从DEI图像中提取出反映物体相位梯度信息的折射角图像.本文在综合研究了光学几何近似方法和多图统计方法等相位信息提取技术之后,提出了``统计--几何光学近似'相位信息提取的新方法, 并在北京BSRF形貌站上进行了实验验证. 实验表明,新方法能够大大提高光学几何近似求解的精确度和折射角图像的信噪比. 相似文献
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By revealing the relationship between edge visibility and imaging parameters in in-line phase contrast imaging (PCI), we propose a method to quantitatively measure the contribution of absorption and phase shift from acquired images. We also prove that edge visibility will grow with the increasing source-object distance and object-detector distance. The result is validated by relative phase factor and by experiments conducted on a microfocus x-ray source. This method provides a new approach to evaluate in-line PCI images and is helpful for deciding imaging parameters. 相似文献
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Influence of tube voltage and current on in-line phase contrast imaging using a microfocus x-ray source 下载免费PDF全文
In-line x-ray phase contrast imaging has attracted much attention due
to two major advantages: its effectiveness in imaging weakly
absorbing materials, and the simplicity of its facilities. In this
paper a comprehensive theory based on Wigner distribution developed
by Wu and Liu [Med. Phys. 31 2378-2384 (2004)] is reviewed. The
influence of x-ray source and detector on the image is discussed.
Experiments using a microfocus x-ray source and a CCD detector are
conducted, which show the role of two key factors on imaging: the
tube voltage and tube current. High tube current and moderate tube
voltage are suggested for imaging. 相似文献
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For weakly absorbing materials, image contrast can be enhanced by
phase contrast in formation. The effectiveness of the in-line phase
contrast technique relies on its ability to record intensity data
which contain information on the x-ray's phase shift. Four kinds of
approaches to the relationship between intensity distribution and
phase shift are reviewed and discussed. A micro-focal x-ray source
with high geometrical magnification is used to acquire phase
contrast images. A great improvement on image quality is shown and
geometrical parameters are modified for comparison between different
imaging positions. 相似文献
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