Translation: I have 87% confidence that this pixel is yellow-green
Chuck Norcutt
On 2/14/2014 12:53 PM, usher99@xxxxxxx wrote:
> CFA--color filter array
>
> B to B--- blue to blue
>
> R to R----red to red
>
> POCS--"Projection onto convex set theory-"--see below excerpt from a
> paper
>
> "Another effective approach of interpolating missing data in
> chrominance channels is to borrow wavelet theory. Based on the
> observation that edges across color channels are highly correlated, it
> is possible to obtain a good estimation of high-frequency band
> coefficients in chrominance from their luminance counterpart by simple
> maxrule (13) or mean-corrected synthesis.(8) More systematic approach
> is based on projection-onto-convex-set (POCS)theory.(21) By alternating
> the projection onto observation and detail constraint sets, chrominance
> channels canbe efficiently reconstructed after few iterations. Since
> POCS-based demosaicing achieves good performance at the price of
> moderate computational cost, it has been widely used as the benchmark
> scheme for later works."
>
> Here is reference 21: FWIW
>
> http://imagenoise.googlecode.com/svn-history/r56/trunk/demosaick/Demosaicing/Demosaicing.pdf
>
>
> Right now if ones uses a converter that avoids the watercolor effect
> (this effect can be seen in that pinkish fabric from the standard
> images on imaging resource) ---
> the trade-off is that you can get these tiny, red-green speckle
> artifacts in very high contrast areas, particularly with specular
> highlights.
>
> Relatively subtle issues except at near 100% viewing though might
> bother some especially landscape photogs that like to print large.
>
> Point is that there should be a computational way to mitigate if not
> eliminate the issues. DXO (from a company rep at a show) had looked at
> the issue and for now decided ( deduced from their forum) waaaay too
> much work to make it a commercially viable project right now to add to
> DXO optics pro.
> (also might take 5min to process a raw file)
>
> Am in shopping mode and seemed to get distracted (Indeed totally lost)
> down some side streets.
>
> ARU, Mike (abbeviations are us)
>
--
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