New Spy Tech Can Recover Voice Imprints From Physical Objectsselfnews Post Even more impressive is that researchers could detect speech from an object photographed from 15 feet away through soundproof glass, as well as analyze video recordings and extract the data from objects in a room even when the people targeted were off camera. You can see the full demonstration of how this visual microphone technology works, and how it combines with other similar discoveries, in three videos posted below. In our era of ever-increasing crazy spy tech, this discovery could open up a whole new array of surveillance applications. 