Welding zone

Automatic detection of welding zones in aluminium

From X-ray CT data of a welded aluminum part the penetration of the plumb and with it the quality of the welding should be automatically determined. The problem is the small difference in the material compositions in the aluminum welding zone against the aluminum part itself. In a normal reconstruction (filtered backprojection) of the CT data this small difference in the material composition is totally suppressed and artefacts of the reconstruction are overlaid.

FORWISS has developed a method which pay regard to the specific peculiarity of the present problem. Herein the whole investigated object is modelled. From this model a new set of CT data is calculated which can be compared with the original measured CT data. In this way the object is eliminated and the area of the welding zone is intensified.

[Image1] [Image2]
Reconstructed object before (left side) and after elimination of the object

The figure shows the reconstructed object (left side) and the difference between the model and the real reconstruction (right side). The area of the welding zone is marked with the green circle. The eliminated object in the left image is sketched with the red line.