在现今的射线检测技术中，作为新生代的数字成像技术与传统的胶片照相相比，由于各自组成的核心部件——数字探测器和胶片具有不同的特点，使得数字成像与胶片照相存在很大的区别，特别是在影响像质因素和像质表征参数方面的区别更加突出。文章旨在通过分析两者的区别，引出数字成像像质的评价指标：对比度和分辨率。通过分析评价指标，强调分辨率的重要性，以引起检测人员的关注，避免单方面要求提高对比度，而减小分辨率，出现细微缺陷的漏检，产生质量隐患。

As a new X-ray inspecting technology, the digital radiography is seriously different from film radiography due to the difference between the digital detector and film. As a result, the image qualities of these technologies have more differences, especially in the influence factors and representation parameters. This paper analyzes the difference between digital radiography and film radiography, advances image quality evaluation parameters for digital radiography technology, i.e. contrast and resolution, and especially emphasizes importance of resolution for inspector to avoid undetected small defect by excessively heightening contrast and reducing resolution.