Thickness calibration and shadow correction for automatic X-ray inspection unit with calibration sheet of known thickness and X-ray absorption placed under object of unknown thickness and absorption

摘要

The calibration sheet (320) has a known thickness (t2) and absorbs a known percentage of the X-rays (330) passing through it. It may be made of copper or plastics material. A test piece (310) is placed on top of the calibration sheet. It may be of a different thickness (t1) and may consist of soldered goods, with a variable absorption of X-rays. The X-ray machine may be of the scanning laminography or tomography type, giving a clear image of one plane in the test piece.