On Thu, Dec 27, 2012 at 12:42 PM, johannes hanika <[email protected]> wrote:
> On Thu, Dec 27, 2012 at 6:19 AM, Pascal Obry <[email protected]> wrote:
>>
>> I have tested the new denoise module a bit more deeply today. I feel
>> that there is something wrong with it.
>>
>> To me the denoise module does too much smoothing of the image and we are
>> loosing lot of details.
>
> it's optimizing peak signal to noise ratio, not subjective detail. i
> like noise, so i think especially for still images, a little noise
> contributes to the perceived detail in the image.
>
>> I'm wondering if this is not because it applies
>> on the chromatic and on the luminance noises. The former is probably ok,
>> but the later is often the cause of details loosing.
>>
>> In fact I'm able to get far better (read here something that is close to
>> what LR4 does) results with the equalizer using only the chroma curve.
>>
>> Would it be possible for the denoise module to do something similar?
>
> not really, it reverses the physical noise on the three sensors (which
> are camera linear rgb, not Lab).
>
> it's probably possible to do some luma/chroma blending after denoising
> with some custom color space conversion in the module.

i take it back. here's how you would do it:

- switch on the denoising module
- enable blending, go to `color' mode
- if you want to denoise luma, too, create another module instance and
use regular blend mode

not optimal and computationally wasteful, but works today.

jo

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