BoatyPrint

He has danced very close the edge with his experiments. However, he appears to be very knowledgeable with what he does.

Diagnosing some internal illnesses without xray or MRI.

Plenty of applications for a Linux box that aren't "nefarious". Maybe digital signage, or backup server, to name two.

I dont believe that by painting over the bright FFT spots you are necessarily removing the high frequencies. Instead, you are removing the strong frequencies from the image. The strong frequencies cause peaks in the FFT image. Its the repetitive nature of the moire effect that cause peaks in the FFT image.