Re: [CinePaint] Really basic script for batch converting.

On Mon, 30 Nov 2009 09:14:20 -0600 (CST)
Bob Friesenhahn <[email protected]> wrote:

> 
> I am not sure exactly what Cinepaint's noisyfy does, 
>

According to the source code, noisify.c, a Gaussian noise is applied.
I would assume that the noise parameter corresponds to sigma, or the
standard deviation.

To visually show this, I created a 6-bit image containing just one
pixel value of 32768.  Here is the histogram of this image, zoomed
down to show the fine detail at the center point:

http://home.comcast.net/~frank.peters/hist-nonoise.png

The single peak has a count of 160000 which is the total size
of a 400x400 image.

Then Cinepaint was used to noisify the image at 0.008.  The histogram
of the result is shown here:

http://home.comcast.net/~frank.peters/hist-noise.png

The count of the original pixel at 32768 has dropped to less
than 500 and other pixels in a small range about the original
value have been created according to a gaussian distribution.

The range of this distribution seems small enough to be undetectable
by the human eye.

Frank Peters


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