This is interesting now as it's a hot topic in the UK. The government claims this technology will finally be in use next year [1]. Apparently, it can detect concealed knives (even under heavy clothing) from 6 metres away using ordinary cameras combined with "electromagnetic infrared waves and a unique computer algorithm" [2]. I imagine this could be used to detect other types of metal weapons used more prominently in other countries.<p>[1] <a href="https://www.bbc.co.uk/news/uk-68085532" rel="nofollow">https://www.bbc.co.uk/news/uk-68085532</a><p>[2] <a href="https://www.standard.co.uk/news/politics/knives-crackdown-zombie-knives-scanners-police-home-office-cleverly-b1134667.html" rel="nofollow">https://www.standard.co.uk/news/politics/knives-crackdown-zo...</a>