Deblurring Images: Can Blur be Reversed?

[martix]

Everyone always says that there is nothing that can ever remove blur from images.
Correct me if I'm wrong, but here's some thoughts:
Blur is a distinct mathematical transformation involving however many parameters. Which would mean that no information is lost in the image(except where the blur sends it out of the bounds of the image - i.e. on the edges).
Which means that given the knowledge of the applied algorithm and its input parameters, one should be able to reverse that transformation and restore (most of) the image back to its original state.
Now, normally you don't have that information, but there aren't that many popular blur algorithms that you wouldn't be able to make a fair guess as to which one and how it was used.

So why are there no programs out there that do that? Or if there are, could someone point me to them?

 

[DaveC426913]

Everyone always says that there is nothing that can ever remove blur from images.
Correct me if I'm wrong, but here's some thoughts:
Blur is a distinct mathematical transformation involving however many parameters. Which would mean that no information is lost in the image(except where the blur sends it out of the bounds of the image - i.e. on the edges).

Yes, information is lost. One pixel can only represent one thing. Say pixel n has a value of 128,128,128, and it is a blur of the two pixels on either side of it. Were the two pixels 0,0,0 and 255,255,255? Or were they 255,128,0 and 0,128,255?

You can't know. Though you can make some guesses based on the likelihood of the changes with the 8 pixels adjacent to n.

So why are there no programs out there that do that? Or if there are, could someone point me to them?

There are. Have you never watched CSI?

http://www.makemymood.com/2009/10/21/csi-zoom-story

 

[robphy]

Possibly interesting:
http://www.nist.gov/lispix/imlab/FFT/deblur.html
http://www.imagemagick.org/Usage/fourier/