[Benn Jordan] had an idea. He’d heard of motion amplification technology, where cameras are used to capture tiny vibrations in machinery and then visually amplify it for engineering analysis. This is typically the preserve of high-end industrial equipment, but [Benn] wondered if it really had to be this way. Armed with a modern 4K smartphone camera and the right analysis techniques, could he visually capture sound?
The video first explores commercially available “acoustic cameras” which are primarily sold business-to-business at incredibly high prices. However, [Benn] suspected he could build something similar on the cheap. He started out with a 16-channel microphone that streams over USB for just $275, sourced from MiniDSP, and paired it with a Raspberry Pi 5 running the acoular framework for acoustic beamforming. Acoular analyses multichannel audio and visualizes them so you can locate sound sources. He added a 1080p camera, and soon enough, was able to overlay sound location data over the video stream. He was able to locate a hawk in a tree using this technique, which was pretty cool, and the total rig came in somewhere under $400.
The rest of the video covers other sound-camera techniques—vibration detection, the aforementioned motion amplification, and some neat biometric techniques. It turns out your webcam can probably detect your heart rate, for example.
It’s a great video that illuminates just what you can achieve with modern sound and video capture. Think SIGGRAPH-level stuff, but in a form you can digest over your lunchbreak. Video after the break.
