- cross-posted to:
- privacy@lemmy.ca
- cross-posted to:
- privacy@lemmy.ca
Pretty cool watch. Probably old news by now on any serious scale though.
He basically isolated some low frequencies (which means they penetrate materials well) of plane engines and calculated based on a few of them a precise location where the video was taken.
Could someone just play a pre-recorded loop of those kinds of subharmonic sounds at low volume in the background of their video in order to mask the real Doppler curves and such in the audio?
I mean yeah. But you can also just filter out the frequencies in post.
They go through this in the video. The frequencies in question overlap with large portions of the vocal range, so not very practical. They also show that it’s pretty easy to recreate the data even when it’s attenuated.
But the filtered out low frequencies will have modulated the higher frequencies of the the intended audio content. More difficult to process but the LF signal is there.
Layering false signals on top just means there’s fake locations to rule out.
And if it’s video: https://news.mit.edu/2014/algorithm-recovers-speech-from-vibrations-0804
this guy F…ourier Transforms