State of the art in upsizing algorithms?

Started Jun 9, 2014 | Discussions thread
JimKasson
JimKasson Forum Pro • Posts: 30,021
Re: State of the art in upsizing algorithms?

Mark Scott Abeln wrote:

Is there any research on going directly from a mosaiced Bayer raw file to an upsampled image? Lately I’ve gotten comfortable with doing my own processing in Octave with good results. Clearly there will be at least some data loss when doing the demosaicing and upsizing steps independently.

I've long thought that was the way to go, but I haven't seen any evidence of commercial tools working that way. Demosaicing involves building a model of the scene based on sparse samples, and that model should be valuable in producing an upsampled result; it seems a shame to throw it away.

Take a look at some of the frequency-domain methods in this survey paper:

http://www4.comp.polyu.edu.hk/~cslzhang/paper/conf/demosaicing_survey.pdf

If you're adventurous, you could use one of the frequency domain methods and effectively do your resampling when converting back to the xy domain. However, my experience with image frequency domain processing is quite limited, and I have seen minor divergence from expected results, even with 64-bit floating point precision.

If you stay in the space domain, there's a possible win in not going to 16-bit integer precision between demosaicing and resampling. That win should be more significant as the scaling methods and sharpening filters get more complex.

Jim

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