X射线成像积分滤波模型与实验

发布时间：2018-03-14 07:40

本文选题：X射线　切入点：对比度　出处：《发光学报》2017年07期 　论文类型：期刊论文

【摘要】：X射线数字化成像系统的不足主要表现在成像末端耦合约束、微焦点约束瓶颈以及单光子成像缺陷与量子噪声约束等方面,利用传统的数字图像处理手段很难实现有效的图像滤波,而复杂的滤波算法进一步限制了其工程使用效果。为了提高X射线成像系统的光学传递能力与系统抗噪声能力,本文首先以热激发X辐射源与X射线像增强器为例,从系统层面探索成像遇到的诸多技术瓶颈,并在此基础上提出了一种针对X射线成像的积分滤波方法。然后,将空间频率固定的铅制光栅作为被测目标,通过改变中继光学耦合系统的物像关系使得像方空间频率在一定区间内连续改变,进而通过大量的实验数据实现在不同积分时间条件下的光学传递函数精确拟合。接着,分别从光学传递函数积分效果与归一化后的基频传递特性的角度验证了该滤波方法可以有效压制热触发源引入的量子噪声,避免图像产生单光子成像缺陷。实验数据表明:该方法可以提升系统成像的光学传递能力。最后,通过帧叠加与积分滤波的对比效果验证了该滤波方法的优越性。
[Abstract]:The shortcomings of X-ray digital imaging system are mainly reflected in the coupling constraints at the end of imaging, the bottleneck of micro-focus constraints, the defects of single-photon imaging and the constraints of quantum noise, and so on. It is very difficult to realize effective image filtering by traditional digital image processing methods, but the complex filtering algorithm further limits its engineering application effect. In order to improve the optical transmission ability and anti-noise ability of X-ray imaging system, In this paper, the thermal excited X radiation source and the X ray image intensifier are taken as examples to explore many technical bottlenecks encountered in imaging system, and then an integral filtering method for X ray imaging is proposed. The lead grating with fixed spatial frequency is used as the target to be measured. By changing the image relation of the relaying optical coupling system, the spatial frequency of the image square can be continuously changed in a certain range. Then through a lot of experimental data to realize the accurate fitting of optical transfer function under different integral time conditions. From the point of view of the integral effect of optical transfer function and the normalized fundamental frequency transfer characteristics, it is verified that the proposed filtering method can effectively suppress the quantum noise induced by the heat triggered source. The experimental data show that this method can improve the optical transfer ability of the system. Finally, the superiority of the method is verified by comparing the frame superposition with the integral filtering.
【作者单位】：长春理工大学理学院;
【基金】：吉林省青年科研基金(20140520122JH,20160520114JH) 吉林省科技发展计划重点科技攻关项目(20150204083GX,20150204049GX) 吉林省教育厅“十三五”科学技术研究项目(吉教科2016357) 国家自然科学基金青年科学基金(51602028) 长春理工大学科技创新基金(XJJLG-2015-02)资助项目~~
【分类号】：O434.1;TP391.41

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