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Canon EOS R3 Baked in Raw Noise Reduction Revisited

Started Jan 21, 2022 | Discussions thread
EthanCam Regular Member • Posts: 111
Re: Canon EOS R3 Baked in Raw Noise Reduction Revisited
1

hjulenissen wrote:

So an analysis of the psf/mtf of the max ISO vs some other ISO might give some insight into the nature of their noise reduction. Is it a per color channel blur? Median filter? Edge preserving?

One might then speculate that noise reduction at lower ISO possibly is of a similar nature, only backed off a bit in degree, kernel size etc.

I've tried out a psf/blur kernel parametrization vs. noise for my canon r6, flat field files at different exposures: https://www.dpreview.com/forums/post/65857338

Note that on the plot, the noise (x-axis) is the observed noise, i.e. after NR, and the NR scaling (y-axis) gives how much the noise has been reduced. So you have to divide by this number to find out what the original noise value was.

It's just an hypothesis at this point, but from that particular test, for the r6, it seems the higher the noise, the weakest the NR (except for the highest ISO value, where NR probably is applied no matter what).

The camera could estimate the noise from the knowledge of the gain and the read noise (optical black pixels) , but it could also be estimated from local areas of the image for example.

Cheers, Ethan

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