I have an ongoing friendly dispute with another member over on Photo Stack Exchange about the fundamentals of how RAW works, and I'm hoping you can settle it.
My understanding is that Bayer demosaicing works basically entirely on the assumption that one can deduce likely color information from monochromatic pixels. That is, for a pixel with a blue filter, you can assume that the correct green value is close to the average of neighboring green-filtered pixels, and the red value close to the average of neighboring red-filtered pixels — even if those filters were to be theoretically perfect.
My site-colleague argues that, as shown in this graph:
the filters have a lot of overlap, and describes the demosiacing algorithms as working because they recover that overlap.
Who is correct here? Would Bayer demosaicing work if the filters had no overlap?
(Bonus questions: would this be an improvement, or actually a downside? Presumably you'd be letting in less light overall; would you get more accurate color for that price? I know that simple averaging "works" for demosiacing; are there more complicated algorithms which do take overlap into effect explicitly?)