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Old 23-07-2018, 03:00 PM
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sil (Steve)
Not even a speck of dust

sil is offline
Join Date: Jun 2012
Location: Canberra
Posts: 1,402
as a osc shooter I have something to add from a different perspective for experimental consideration. In photography to convert colour to black and white its not a linear process there is filtering involved to accentuate or soften contrast, eg orange filter can deepen sky and highlight clouds for interest, you can make redness and pimples disappear to enhance skin. The initial test comparison of colour image versus one with artificial channel is not a valid approach. Instead I think you need to linearly convert both colour results back to grey and then those can be compared. You could subtract or difference to get a perfectly featureless grey image (if both colour images match) and measure the amount they differ since you won't get a perfect match with an artificial process.

What you will get though is a repeatable process with a quantifiable number ( no " i adjusted and it looks about right", mathematics rules optics and colours so definable adjustment numbers can be honed at to get the final two grey images as closely matched as possible. That will allow people to say "this process works well to build missing B channel while this other process works better on missing R".

Seems like its something that can be pursued, just be careful how you obtain a grey or L from colour data. Using subs from a OSC you can split those to RGB then throw away one channel at a time and work on technique to rebuild them , you then compare to source RGB data and should match. first split then remerge all to rgb and compare should give you 100% match, do this to test your processing method and software. You could also try different colour spaces for your source data as information gets lost converting those.You might discover capturing in srgb and rebuilding missing channel never gets you better than 90% match while capturing in adobergb alone takes you to 95%. So you could prove how much or how little capture setting impact final results. so much to explore even without knowing the maths.
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