为推动X射线数字成像技术在生产中的应用，需要有效解决数字图像中缺陷影像评定问题。数字射线扫描检测的特点易造成检测图像存在放大与变形，从而不利于缺陷评定。为解决上述问题，设计加工了专用的数字射线检测图像评定尺，并将其应用于生产检测实际。使用效果表明，图像评定尺可方便、准确地实现数字图像中缺陷的定量评定。

To accelerate application of digital radiography(DR) in practice, the problem that how to evaluate the defects in corresponding digital images should be solved. The digital images acquired by DR system with linear array detector are likely to be magnified and distorted, thus make against defects evaluation. To solve the problems mentioned above, scale specimen for image evaluation was designed and applied in DR. It showed that with the help of scale specimen, defects evaluation can be achieved easily and accurately.