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Re: [OM] Upsampling/Sharpening technology [was E system metering was Dpr

Subject: Re: [OM] Upsampling/Sharpening technology [was E system metering was Dpreview Challengesbeta: Firstwinners]
From: Chuck Norcutt <chucknorcutt@xxxxxxxxxxxxxxxx>
Date: Sat, 17 Jan 2009 20:49:23 -0500
Yours is better but I think half of the improvement is getting rid of 
the ugly reddish color cast around the eye.

Chuck Norcutt


Moose wrote:
> usher99@xxxxxxx wrote:
>> Oh,
>> I found the site that  piqued my interest in the deconvolution 
>> routine.(R-L iteration).
>>
>> http://www.clarkvision.com/imagedetail/image-restoration1/index.html
>>   
> 
> The R-L processing is interesting and, in the example, clearly a bit 
> better than USM. But lets get right down to it. Anyone interested in 
> this stuff, I'd appreciate your votes on the alternates here. 
> <http://www.moosemystic.net/Gallery/tech/ARL_Sharp/Fox.htm>
> 
> Problems I see with his presentation and examples, which also mostly 
> explain the above:
> 
> - He refers to an end use of a print, yet never shows scans of prints 
> nor comments on any visible differences in actual prints of various 
> sizes. He doesn't seem to know about, at least doesn't mention, the 
> different sharpening needs for web display vs. printing. Images 
> optimized for printed output will generally look over sharpened, even 
> 'crunchy' when viewed on screen.
> 
> - He does not compare it to more sophisticated approaches to sharpening. 
> The techniques in Bruce Fraser's book "Image Sharpening", Fred Miranda's 
> sharpening plug-ins and undoubtedly numerous others offer different and 
> often more effective sharpening than simple uses of USM - and without 
> the extreme processing overhead penalty.
> 
> - He only tries one up-sampling option. There are better tools 
> available. Qimage and other, more expensive and often specialized RIPs, 
> may use both more sophisticated up-sampling algorithms and different 
> sharpening algorithms, both optimized for printing, rather than viewing.
> 
> Based on what I see in his examples, it appears that the R-L processing 
> makes full pixel and upsampled images look better on screen than does 
> simple USM. My rough guess is that in a print of his side by side 
> example at his specified magnification, the USM version will look 
> better, sharper, clearer, than the R-L version at any normal viewing 
> distance.
> 
> For the screen? I think I've equaled or bettered his AR-L result using 
> far less exotic and processor intensive tools. I would not use any of 
> them for printing.
> 
> Moose
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