Deconvolution sharpening revisited

[Fine_Art]

Here is a very fast sharpen of a crop. 2 ground squirrels printscreen to paint.

This took maybe 3 seconds due to the small size. A full 16MB picture would be about a minute. Its a multi-threaded 64 bit program.

[jguentert]

For all those who are interested in deconvolution like me this may be interesting: I'm still searching for a convincing solution for the Mac. I bought Topaz InFocus but I am not satisfied with it. I would pay a lot to get the not perfect but easy to use Focus Magic – updated for CS 4 or 5 (without the need of Rosetta) or Caron with a more convenient Mac interface.

But meanwhile I found sth. relatively new in this special field: Back In Focus Currently implemented algorithms: Unsharp masking (fast and full), Wiener finite and infinite impulse response, Richardson-Lucy (with a thresholding variant), Linear algebra deconvolution.

"Back In Focus" is absolutely not for beginners. It took me some days to learn how to use it – and here's room for improvement. But once you got how to use it – you'll get better pictures.

http://www.metakine.com/products/backinfocus/

Example:

[BernardLanguillier]

"Back In Focus" is absolutely not for beginners. It took me some days to learn how to use it – and here's room for improvement. But once you got how to use it – you'll get better pictures.

http://www.metakine.com/products/backinfocus/

Thanks for the link, it sounds interesting.

Would you say its main strenght is to further improve the detail of sharply focused images, or it is more devoted to recovering blurred images (hand shake, focus softness,...)?

Cheers,
Bernard

[EricWHiss]

Thanks, I'll give this a whirl.    I do like Caron, much better than topaz.    I know there also must be some tools for imageJ but haven't tried any.  Has anyone tested any deconvolution plugins for imageJ that they like?

[jguentert]

It's definetly devoted to recovering blurred images.

[BernardLanguillier]

It's definetly devoted to recovering blurred images.

Thanks for the feedback.

Cheers,
Bernard

[EricWHiss]

Well, this is not exactly intuitive and at least some of the routines run very slow. 

[sjprg]

Hey guys, has the interest waned again, or have we beat the subject to death? I don't have the math to contribute but I do have an interest in following the discussion.
Regards
Paul

[walter.sk]

Back In Focus Currently implemented algorithms: Unsharp masking (fast and full), Wiener finite and infinite impulse response, Richardson-Lucy (with a thresholding variant), Linear algebra deconvolution.

I tried downloading it but couldn't install it on a Windows machine.  Is it only for MAC?

[sjprg]

MAC only

[walter.sk]

MAC only

Hmmm!  Oh, well.  Now, if they would only upgrade Focus Magic to 16Bit or more.  With all of its faults I had found it the best for "capture sharpening."

[bjanes]

Hmmm!  Oh, well.  Now, if they would only upgrade Focus Magic to 16Bit or more.  With all of its faults I had found it the best for "capture sharpening."

I see that Focus Magic will have a beta for 64 bit windows in January 2013 and for the Mac in March 2013. AFAIK the old version does support 16 bit files, but I have not used it for some time since I upgraded to 64 bit windows. One can use it with 32 bit Photoshop, but it is a pain to switch back and forth between 32 and 64 bit.

Bill

[sjprg]

I write them about 4 times a year requesting an update. They keep responding "we are too busy on other projects"
Hopefully someday they will give us an updat. They had the best available. In the meantime I use ACR 7.3 at
amount=0, radius=.5, detail=100 which seems to work very well.
Regards
Paul

[Fine_Art]

I think you are fixating on the particular implementation (that Bart used) rather than considering the method in general.  Typically most of the improvement to be had with RL deconvolution comes in the first few tens of iterations, and the method can be quite fast (as it is in RawTherapee, FocusMagic, and RawDeveloper, for instance).  A good implementation of RL will converge much faster than 1K iterations.  It's hard to say what is sourcing the ringing tails in Bart's example; it could be the truncation of the PSF, it could be something else.  I would imagine that the dev team at Adobe has spent much more time tweaking their deconvolution algorithm than the one day that Bart spent working up his example.

But I would ask again, why do you want to throw dirt on deconvolution methods if you are lavishing praise on ACR 6.1?

This thread was linked in a current thread so I am bringing up my 2 bits years later.

I have been using deconvolution for years. Sometimes in an image I can find something that lets me use the custom PSF function in images plus. When this happens a single cycle of deconvolution dramatically improves the image blur. Further cycles using that PSF actually dont work better than a regular function like a gaussian for the obvious reason that that PSF no longer matches the state of the image. To really use a good custom you have to modify it each cycle as the image is improving.

Using a 1000 cycle approach is fine if you use a very mild under-correction wanting it to converge to something. I have never gone more than 250 cycles with a mild function because I simply do not see further improvements. I mostly use 3x3 gausssian for example even If I know it needs a couple cycles with a 7x7. The artifact damage to other parts of the image is much less.

My rule of thumb is if I cant do it with 50 cycles I am using the wrong function. Usually I just use 10 cycles. Sometimes less, I have images where I stop after 3 cycles of a 3x3 gauss, the lightest the program runs.

[BartvanderWolf]

This thread was linked in a current thread so I am bringing up my 2 bits years later.

Hi Arthur,

The thread is as relevant today as it was when it was started. No problem with people adding to it. RawTherapee just a few days ago improved the speed of its RL sharpening implementation, and FocusMagic is beta testing the long overdue 64-bit version of their plugin. So the subject is very much alive.

I have been using deconvolution for years. Sometimes in an image I can find something that lets me use the custom PSF function in images plus. When this happens a single cycle of deconvolution dramatically improves the image blur. Further cycles using that PSF actually dont work better than a regular function like a gaussian for the obvious reason that that PSF no longer matches the state of the image. To really use a good custom you have to modify it each cycle as the image is improving.

That depends on the algorithm used, but in particular the Richardson-Lucy deconvolution is an iterative algorithm that internally iterates to optimize certain parameters. It's not simply a repetition of the same deconvolution with the same PSF.

To demonstrate that multiple iterations do serve a purpose, especially with a low noise image, I've created the following example:

Here is the test target that was used for the following demonstration:

Here is the sigma=1.0 PSF that was used to convolve (blur) the image, and then deconvolve the blurred 'star' version.

Click on the image to get a higher accuracy 32-bit floating point TIFF version of the PSF

Here is the convolution result:

Here is a RL deconvolution result after 10 iterations, resolution has improved:

Here is a RL deconvolution result after 100 iterations, it has better resolution:

Here is a RL deconvolution result after 1000 iterations, it has even better resolution, however not all resolution could be restored.
When the blur reduces the image detail to zero contrast, then all is lost:

The RL implementation used was from PixInsight Version 1.8, and I used the unregularized RL version, because there was no noise in this artificial (CGI) image.

My rule of thumb is if I cant do it with 50 cycles I am using the wrong function. Usually I just use 10 cycles. Sometimes less, I have images where I stop after 3 cycles of a 3x3 gauss, the lightest the program runs.

Often, 10 or 20 iterations are plenty, especially with some noise in the image and a less than perfect PSF (which is the common situation). I do see a benefit in 'rolling your own PSF', because it allows to make more accurate versions than the few default ones that many programs offer. Since Gaussian shaped PSFs are often close to ideal, my PSF generator tool can assist in producing a number of PSFs to choose from. The numerical data can be copied and pasted into a text file, which e.g. ImageJ can import as a space separated text image file, for those applications that take a PSF image as input. Others will need to copy and paste the data into dialog boxes.

Cheers,
Bart

[Fine_Art]

Bart I understand the role of iteration. What I am referring to is "custom" PSFs not standard distributions. A custom to me is something selected from the image.

Your demonstration is running a math function on a chart then reversing it with iterations of a standard Gaussian. The problems we have out in nature are imperfect lenses, front focus/back focus, tripod vibration, shutter vibration. The FF/BF component would be handled nicely by a Gaussian. The rest need something else which you can only find in the image itself. If you do select some strange shape from the image it will make the blur better fast or not help much. If it does help you need to switch to something else soon or it just starts to make another mess.

[Fine_Art]

Here is an example ofwhere I could find a "custom" PSF.

There was wind against the building while the fireworks were going. There was also the big booms of the larger shells. Looking around through the full size images I can probably find lights that should be perfectly round. many will be odd shapes from being reflected in glass. If I make a good selection I can remove almost all the problems of the shot.

[Fine_Art]

So in that shot I found some rich person had been useful enough to get a chopper to watch the Canada day fireworks. I just watched them from my balcony .
In the first 200% zoom you can see the oblong PSF of the chopper's safety lights. I pick that as a test "custom" then cut a piece out of the rest of the shot to test it on.
In the second screenshot you can see the impact of 2 cycles. The first cycle was an improvement. The second is starting to make halo edges. If I keep goin it will make a mess.
So if that really was a better PSF than another I find in the shot I would re-sample it after the cycle. It would be a new different PSF.

[Fine_Art]

Here is a the original unsharpened in the middle
10 cycles  of gaussian 5x5 on the left
custom on the right.