> "We start out by transmitting a random white noise signal. But we are generating this random signal, so we know exactly what the randomness is," said first au

> "We start out by transmitting a random white noise signal. But we are generating this random signal, so we know exactly what the randomness is," said first author Anran Wang, a doctoral student in the Allen School. "That signal goes out and reflects off the baby. Then the smart speaker's microphones get a random signal back. Because we know the original signal, we can cancel out any randomness from that and then we're left with only information about the motion from the baby." Reading between the lines of this, it sounds like these folks found another clever use for adaptive filtering. I wonder how well this plays along with whatever adaptive filtering is already going on inside an Amazon Echo? As I've learned more about the guts of voice speakers' signal processing, I've come to realize that adaptive filtering plays a huge part in making modern acoustics and telecom possible. It's a super cool subset of signal processing if you're interested in that sort of thing. https://www.mathworks.com/help/dsp/ug/overview-of-adaptive-filters-and-applications.html https://www.mathworks.com/help/dsp/ug/overview-of-adaptive-f...