CEA Valduc uses several X-Ray generators to carry out many inspections: void search, welding expertise, gap
measurements, etc. Most of these inspections are carried out on silver based plates. For several years, the CEA/Valduc
has decided to qualify new devices such as digital plates or CCD/flat panel plates. On one hand, the choice of this
technological orientation is to forecast the assumed and eventual disappearance of silver based plates; on the other hand,
it is also to keep our skills mastering up-to-date.
The main improvement brought by numerical plates is the continuous progress of the measurement accuracy, especially
with image data processing. It is now common to measure defects thickness or depth position within a part. In such
applications, data image processing is used to obtain complementary information compared to scanned silver based
plates. This scanning procedure is harmful for measurements which imply a data corruption of the resolution, the adding
of numerical noise and is time expensive. Digital plates enable to suppress the scanning procedure and to increase
resolution. It is nonetheless difficult to define, for digital images, single criteria for the image quality. A procedure has to
be defined in order to estimate quality of the digital data itself; the impact of the scanning device and the configuration
parameters are also to be taken into account.
This presentation deals with the qualification process developed by CEA/Valduc for digital plates (DUR-NDT) based on
the study of quantitative criteria chosen to define a direct numerical image quality that could be compared with scanned
silver based pictures and the classical optical density.
The versatility of the X-Ray parameters is also discussed (X-ray tension, intensity, time exposure). The aim is to be able
to transfer the year long experience of CEA/Valduc with silver-based plates inspection to these new digital plates
supports. This is an industrial stake.