First, let me introduce myself - I am the Managing Director of FixerLabs, I suppose I am a "lurker" on PRODIG.
I hope you don't mind me contacting you directly.
I found this email you sent to PRODIG some while back and wanted to comment on your suggestion that
FocusFixer is a form of Unsharp masking.
USM is a crude form of deconvolution more like high-pass filtering or sharpening - it works reasonably well for slightly soft images.
FocusFixer is quite different. It uses a technique known as deconvolution. It has a model of the ideal lens blur (or point spread function)
and attempts to computationally invert the optical process that generated the blur or softness. USM has no such model.
Unsharp masking is a computationally simple filtering process (hence it is one-pass and fast).
FocusFixer is iterative, moving in a series of small steps to the solution. Each step is (perhaps) five times more
computationally demanding than USM and it requires 20-40 steps to get to a solution.
The benefit is that FocusFixer does a better job on soft images and out-performs USM dramatically when
focus blur is more evident.
I am in the process of writing a "white-paper" on USM v. deconvolution techniques (such as FocusFixer) and
wondered if you would share with me the typical parameters you use for USM. So far I have had a few surprises - in particular the colour
artifacts that USM (in Photoshop 7) produces as a side-effect of noise amplification.
Incidentally, we have made some changes to FocusFixer since your post to PRODIG. The latest release gives greater control over
the results for the slightly soft end of the blur scale. If you would like to try it and let me know what you think I would be delighted.
Best regards
Tim Atherton FixerLabs
On 20 Sep 2003, at 9:52 am, Michael Wilkinson wrote:
Have any of you tried out Photoshop the plug ins from
http://www.fixerlabs.com
They have a "Focus fixer" Noise fixer and Shadow fixer.
all available for a free trial period of 20 uses or 20 days.
At first try the focus fixer (commonly known as Unsharp mask ) seems to work well,I have
not tried the others yet.
Any Opinions anyone ?
Regards
Michael Wilkinson. 106 Holyhead Rd, Ketley, Telford, Shropshire. England .TF1 5DJ
44 (0) 1952 618986. www.infocus-photography.co.uk
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