Researchers have adapted the same technology that allows an unborn infant to be imaged in the womb. Ultrasonic signals are able to image the unique ridges and valleys of a fingerprint and also the surface of the skin below it to generate a truly unique way to identify a human. The chip is nowhere near as powerful as the ultrasound equipment thats able to see a growing baby, but it also doesnt need to be. It uses low-depth, ultrasonic signals that are.”]
Source: https://gizmodo.com/3d-fingerprint-scans-could-be-the-ultimate-security-too-1715134095