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loki130 t1_j9qm08v wrote

Reply to comment by hatsune_aru in Why can’t you “un-blur” a blurred image? by so-gold

In the extreme case, if you take an entire image and average it to a single color, clearly you can't reconstruct any detail from that no matter how clearly you know the algorithm. I think a similar argument could be made that a large image split into 4 quadrants that are each completely averaged would also be unrecoverable. Perhaps there is some floor of smaller blur radius where the image becomes recoverable, but I don't think it's obvious that knowing the blur process always allows reversal.

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hatsune_aru t1_j9qmunn wrote

I like to think of that extreme example as "edge effects". Obviously there are limitations to the recovery technique, but "deblurring" is absolutely a thing both in imaging and similarly in non-imaging applications.

https://en.wikipedia.org/wiki/Blind_deconvolution

In a sense, electronic engineering (which I can say I'm a specialist in) concepts like emphasis, equalization, etc are just compensations for channel effects, which one could think as time varying signal equivalents for blurring in imaging.

In that sense, recovery of a "blurred" signal via equalization is absolutely used everywhere that uses high speed digital signals like USB, DDR, PCIe, etc.

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loki130 t1_j9ri1xj wrote

Then why are you saying everyone is wrong when they're pretty much all mentioning that deblurring methods exist but don't amount to perfect image recovery?

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