Salvage that blurred image with blind deconvolution.. for free..

[Fumesucker]

After a good deal of searching I have found a freeware which will do blind deconvolution on normal, terrestrial photographs. Blind deconvolution is commonly used in astronomical imaging to help compensate for a variety of problems in that kind of photography.

http://www.hamangia.freeserve.co.uk/

Here is an example of what blind deconvolution can do for our normal pictures, this is a somewhat out of focus image of a tufted titmouse on our feeder, the second version has been processed with Unshake, a blind deconvolution freeware.





A few notes from the instructions for Unshake..

First, note that Unshake works with pictures with widths and heights of 64, 128, 256, 512... pixels. If you give it a picture with a width of 257 pixels, it will pad it out (with an averaged colour) to 512 pixels, and will take much longer to process it than it would a picture with a width of 256 pixels. (This is a property of the Fast Fourier Transform algorithm which it uses.) 2048 by 2048 is the largest image which can be processed at the moment.

Crop all borders and edges from the image, and try to avoid features added after the picture was taken, such as writing. The reason for this is that such features are usually sharp, and so become distorted when the rest of the image is sharpened.

Try not to adjust the brightness and contrast of the picture, or if you must, ensure that the "gamma" is set to be linear - this may be indicated by a straight line on a graph. Failure to do this puts ripples or ghosts around edges with high contrast.

A disclaimer: Unshake has difficulty with images which are overexposed, underexposed, twisted (meaning that the image turned round an axis between the camera and the subject), or covered in fluff. So don't try to process images of playful black kittens in coal-sheds at night, after the kitten has walked across your scanner.

It took me some experimentation to get good results from Unshake, it's not particularly intuitive or user friendly and larger images can take considerable time to process, there is a *lot* of math going on here and that that takes processor power.

Another example, this time of getting finer detail out of an already fairly decent image..

[Celebration]

1. you did a great job with your images

I'm impressed.

But once you said it wasn't particularly intuitive or user friendly, I will probably pass. Thanks for adding that for those who are challenged enough trying to figure out our camera settings.

[Fumesucker]

2. It's one of those things you have to play with a bit to get the hang of..

It's really only worth the effort to salvage that special image that would be a real keeper except it's not as clear as you would like.

Just another tool in the toolbox, you don't use a hammer when a screwdriver is called for, likewise you don't use blind deconvolution when a touch of unsharp masking will do what you want.

It's free to download and play with, I just happen to get a kick out of trying out and learning new techniques. When I used to do renovations I had more tools than anyone else because I would buy (or even make) a tool to make a certain task easier and might not use it again for five years, but it was there if and when I needed it. I don't watch TV and I'm an insomniac so a lot of time that many people would pass like that I end up trying out different things in photography and a lot of other areas as well.

[JeffR]

3. Thanks for this, Fumesucker.

Fascinating stuff. I use music production software that relies heavily on FFT filtering of audio, and depending on file size, what may strike the end user as a real straightforward operation can really tie even a fast processor up for quite a while.

Going to have to try this on some shots I've written off as useless.