Detection and 3-D positioning of small defects using 3-D point reconstruction, tracking, and the radiographic magnification technique

•3-D positioning of small defects using X-ray radiography.•Experimental capability study.•Tracking based solution shown to relax the requirements on the radiographs.•Shown to work between two and ten times magnification.

In this paper the capability of a 3-D point reconstruction algorithm based on multiple hypothesis tracking is experimentally explored on a setup consisting of a microfocus X-ray source and a digital detector array. The algorithm is verified to detect and 3-D position steel particles with diameters 0.16–0.26 mm radiographed behind 4.7 mm Inconel 718 at two to ten times magnification. At ten times magnification the algorithm is verified to detect and 3-D position with an average error of 0.1 mm pore defects with diameters 0.05–0.25 mm in 4.7 mm thick titanium alloy laser welds.