The Noise Reduction Transformation

[Bob Walker]

Hi,

I would like to play with the Noise Reduction Transform -- is there documentation somewhere that I did not find, but should have?? I'm curious what the various levels are -- same as what applies to the RAW dialog?

Thanks,
Bob W

[ksinkel]

There is a Help page on the Noise transformation. You can display it by hitting F1 while the transformation window is active.

Incidentally the Noise transformation's usefulness is not limited to just dealing with noise. It can be used anytime smoothing is desired, such as smoothing skin tones in portraits.

Kiril

[tomczak]

I find it quite useful for sharpening with v. low threshold. Halos are less pronounced and 'held' closer to sharpened edges than in USM, plus threshold can divide the image into 'smoother' part, such as noise, that can be smoothed, and 'rougher' parts, such as details, that can be sharpened, all simultaneously!

Levels are similar to blurring radius. Level 1, in sharpening, will restrict the halos to exactly 1 pixel. Higher levels will spread the overshoot and undershoot farther from the sharpened edge, but the halo will die off much quicker than in USM the the like. Setting threshold to zero will do sharpening only.

If there was some way that chroma noise could be separated somehow and dealt with too, that would be awesome...!