常用胶片分类标准的比较

The Comparison of Common Classification Standards for Film System

简要介绍了国家标准GB/T 19348.1、欧洲标准EN 584-1和美国标准ASTM E 1815对胶片系统的分类,胶片系统分类常用指标及其含义。指出各个国家射线标准胶片分类的体系略有不同,但其胶片系统的分类依据都是按梯度、颗粒度和梯度-噪声比的数值大小来划分的。通过对不同标准所规定的常用指标限值大小的对比,找出了不同胶片分类系统之间的关系和等价性。

This article briefly introduced the classification standards for film system,including China National standard GB/T 19348.1,European standard EN 584-1 and American standard ASTM E 1815,as well as the common indexes for system classification and its definition.Although there are the different systems for X-ray classification standard in every country,the film system classification are according to the values of gradient,granularity and gradient-noise ratio.Through comparison of common indexes specified in the different standards,the relation and equivalence of different film classification system were found out.