Through-skin pilot-hole detection and localization with a mechanically translatable atomic magnetometer

We demonstrate through-skin electromagnetic induction imaging of pilot-holes in an aluminum block concealed by a 0.41 mm thick aluminum shield with a 1.49 kg mechanically translatable radio frequency atomic magnetometer. The pilot-holes are identified and localized with submillimeter accuracy both with and without the Al shield. We utilize a dual-frequency technique to isolate the image of the target while removing the effect of the shielding from the image. Imaging accuracy is shown to be robust in a range of different operating conditions and immune to the effect of a thermal insulator between the shielding and the target. The approach introduced here finds direct application in aircraft wing manufacture and is competitive with existing approaches. (C) 2022 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study demonstrates the through-skin electromagnetic induction imaging of pilot-holes in an aluminum block concealed by an aluminum shield. The accuracy of imaging is ensured with submillimeter accuracy using a dual-frequency technique to remove the effect of the shielding. The proposed imaging approach is robust and immune to the influence of a thermal insulator, showing potential applications in aircraft wing manufacture.