This paper describes a technique whereby a radiograph is taken of the piping, and the remaining wall thickness is derived using the pixel value of the digital image rather than the profile of the pipe edge . A CR system was used for this work, as it is easier and more accurate to extract the information required from this technique than from film radiography. The CR system also has a set of algorithms that allows analysis of the variation in the pixel value pattern across the radiograph, which was useful for this project. The technique that was developed for this application will be described, along with a test case that was compared to an AUT (automated ultrasonic testing) inspection. This technique of using pixel value (or equivalently film density) to determine pipe wall thickness has been used for a number of years.

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