转换屏背底散射对图像对比度的影响研究

Study on image contrast affected by scattering from the back side of a convertor

分析了高能X光照相中转换屏的背底散射(对可见光的散射)对图像对比度的影响,建立了相应散射影响的计算模型;同时还通过计算模拟给出了相应的结果,理论和实验研究表明对转换屏背底的处理是极为重要的。

In high energy Xray radiography system , CsI convertor is usually used to convert the Xray image into a visible image which can be recorded by other high sensitive image system . The scattering light from the inner side of the convertor can reduce the image contrast and the spacial resolution will degrade. In the paper ,one evaluation method about the influence on the image contrast is set up and some calculated results are given to show this . The tests have proved that the process on the back side of the convertor is the most important thing and that the scattering coefficient of the back side must be reduced to a very small level to keep the image contrast.