应用CCD器件测定增感屏胶片系统的调制传递函数  

Testing the MTF of film screen system with CCD

作　　者：曹厚德[1,2] 王桂英[1,2] 季银宝 黄柳红[1,2] 丁志华 范志峰[1,2] 沈建国 

机构地区：[1]上海市静安区中心医院 [2]中国科学院上海光学精密机械研究所

出　　处：《中华放射学杂志》1998年第7期483-486,共4页Chinese Journal of Radiology

摘　　要：目的论证应用电荷耦合器件（ＣＣＤ）测定屏片系统调制传递函数的可行性，并给出一种适用于ＣＣＤ测试数据处理的方法。方法将４种增感屏和４种胶片组合成１６种屏片系统，分别用ＣＣＤ测试其调制传递函数（ＭＴＦ），并与无屏照片及显微光学密度计测试结果相比较。结果由于ＣＣＤ与显微光学密度计的动态范围存在着一定的差别，前者在１０４数量级，后者则在１０５数量级上，所以测试结果有一定的误差。但由于误差甚小（仅为１／１０００左右），因此在Ｘ线摄影技术的范围内，并不影响其实用价值。所以用ＣＣＤ取代显微光学密度计测试屏片系统ＭＴＦ是完全可行的。结论确认应用ＣＣＤ器件和图像处理系统替代光密度计评价成像质量不但具有快捷、方便的优点，并且可进行计算机处理，所以是一种较先进的方法。Purpose To discuss the feasibility of testing the modulation transfer function (MTF) of film screen system by charge coupled devive(CCD) and the method to process the testing data. Methods 4 type of films and screens were used to get 16 combinations of screen and film. The CCD testing data was compared with that using densitometer and film. Results There was a certain error in our results due to some differences between CCD and microdensitometer, the former was 104 class and the latter was 105. However, this error was very small(only about 1/1 000), being negligible in pratical radiography. Therefore, it was feasible to use CCD instead of microdensitometer to test MTF of film screen system. Conclusion It is quick and convenient to evaluate the image quality of film screen system with CCD instead of densitometer, and automatic computer processing,is possible with CCD.

关 键 词：X线胶片 X线增感屏 傅里叶分析 调制传递函数 

分 类 号：R814.3[医药卫生—影像医学与核医学]