Dr. D writes
>>No, you've got it. I know diffraction is frequency related but I
didn't
>>understand the rest of what you said about sharp cutoffs. You're now
>>the leader. :-)
Point-spread deconvolution will not work all that well to fix blur due
diffraction from a small aperture.
Recall form the real Dr. D's link that on FT sensor by F11 max
resolution is down to about 4MP overall and 3MP
with red light.
http://www.luminous-landscape.com/tutorials/resolution.shtml
Unlike diffraction blur ,Gaussian blur "leaks" enough high frequency
information into the image that it can be boosted and reconstructed
(indeed, a gaussian is a very special extremum case that results in max
blur for the least loss of high frequency detail)
found the below images--not perfect but good enough
original image:
http://praetoriusphoto.images.s3.amazonaws.com/fmforums/20120322_deconvolution/sinsweep.jpeg
added diffraction:
http://praetoriusphoto.images.s3.amazonaws.com/fmforums/20120322_deconvolution/diffracted_sweep.jpg
note how detail frequencies above the cutoff are almost completely
wiped out.
Gassian blur added:
http://praetoriusphoto.images.s3.amazonaws.com/fmforums/20120322_deconvolution/gaussian_sweep.jpg
note gradual reduciton of high freq info rather than cut-off.
Dr. Dp (Diffraction protege)
I trust Dr. D dosen't mind me keeping the training wheels on a while
longer
--
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