Re:Blur Tools for Signal
by cochne on Thursday June 04, 2020 @11:46AM
(#23418160)
Ironically I think a Gaussian blur is one of the few transforms that should be totally reversible. Since the Fourier transform of a Gaussian kernel is also Gaussian, it is nonzero everywhere, meaning you can in theory just divide the Fourier transform of the image by the Fourier transform of the kernel to get the original back :)
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The quantization to the image colorspace and depth is probably the limiting factor, moreso if dithering is used.
As the resolution increases, the ability to reconstruct a lower resolution image goes up as well, which will be more than enough for most identification purposes.
Security as an accidental quality of a system is not security.
Fair point. Elsewhere in thread it looks like they are using a fixed resolution. I guess at that point it comes down to whether they've left enough mid-frequency content for an algorithm to identify the slightly darker/lighter patches of facial features, and whether that spacing can actually identify a person.