Doom9's Forum - View Single Post - How to denoise clip with large grain size? (sample included)

ph4nt0m · 20th July 2016, 10:46

I'm trying to find a suitable filter to reduce very heavy noise. Please have a look at this sample: http://www28.zippyshare.com/v/6M3siEiN/file.html

What makes this type of noise different from other ones I had to tackle until now is that the "grain size" seems to be very large. In other words, it looks like there are blocks of about 2x2 pixels instead of single pixels which make up the noise pattern. Many of the well known filters seem to work on a smaller scope, and therefore they are not very effective against this specific type of coarse noise.

While FastDegrain() does a reasonable job, it seems to miss the noise completely in one scene (might actually be a no-op, haven't verified):

TemporalDegrain() works better in this case, but still a lot of grain remains. Moreover, in the first part of the sample, TemporalDegrain() leads to an unnatural, washed-out result (look at the leaves in the upper right part):

Are there any filters (or combinations of filters) that might be more effective? Usually, I'm not the one who tries to remove every bit of noise, but this coarse grain is really unsightly in my opinion.

Thanks in advance!

20th July 2016, 10:46	#1 \| Link
ph4nt0m Registered User Join Date: Jul 2013 Location: Germany Posts: 13	How to denoise clip with large grain size? (sample included) I'm trying to find a suitable filter to reduce very heavy noise. Please have a look at this sample: http://www28.zippyshare.com/v/6M3siEiN/file.html What makes this type of noise different from other ones I had to tackle until now is that the "grain size" seems to be very large. In other words, it looks like there are blocks of about 2x2 pixels instead of single pixels which make up the noise pattern. Many of the well known filters seem to work on a smaller scope, and therefore they are not very effective against this specific type of coarse noise. While FastDegrain() does a reasonable job, it seems to miss the noise completely in one scene (might actually be a no-op, haven't verified): TemporalDegrain() works better in this case, but still a lot of grain remains. Moreover, in the first part of the sample, TemporalDegrain() leads to an unnatural, washed-out result (look at the leaves in the upper right part): Are there any filters (or combinations of filters) that might be more effective? Usually, I'm not the one who tries to remove every bit of noise, but this coarse grain is really unsightly in my opinion. Thanks in advance!