Research on a DS-class X-ray film digitisation device and an image enhancement algorithm with 12-bit RAW data

Abstract

Automatic evaluation of the X-ray films of welds is an important area of study in the field of non-destructive testing (NDT). A digitising device for the X-ray film is the key to realising automatic evaluation and its image quality directly determines the quality of the automatic evaluation system. At present, the imaging quality of most mature digitising systems on the market cannot meet the DS-class requirements of international standard EN 14096. In order to solve the problems of low visual contrast, detailed information that is difficult to distinguish and low visual resolution in existing digitising systems, a high-quality embedded X-ray film digitising device, processing films with adjustable width, is developed in this paper. The device uses a 12-bit camera and has the characteristics of small size, simple operation and easy maintenance. In order to improve the imaging quality, an optical visual enhancement model is constructed for the generated 12-bit RAW data, which can improve the display of the data. The MTF20% values of the device in the horizontal and vertical directions are 7.544 and 7.460, respectively, and the optical density range is 0.5-4.5 D, the comprehensive index of which can reach DS class. The device has been initially applied by non-destructive testing companies.