[pxmpxm]

I guess on a more general level, I'm confused why a metal detector with bit some machine learning on top wouldn't make a better widget? You'd think that different shape metal object produce different magnetic flux, and there's probably more dimensions to that than just size?

[imtringued]

If it's just a gate that you are walking through then it's all or nothing. Basically just a metal detector.

If you have a conveyor belt system and a CT scanner like setup then yes, you could build a better metal detector.