4.3.  Scatter RGB

Revision History
Revision $Revision: 1922 $ 2006-11-19 j.h

4.3.1.  Overview

Figure 15.68.  Example of applying the Noisify filter

Example of applying the Noisify filter

Original image

Example of applying the Noisify filter

Filter “Scatter RGB” applied

You can find this filter through FiltersNoiseScatter RGB.

The Scatter RGB filter adds a normally distributed noise to a layer or a selection. It uses the RGB color model to produce the noise (noise is added to red, green and blue values of each pixel). A normal distribution means, that only slight noise is added to the most pixels in the affected area, while less pixels are affected by more extreme values. (If you apply this filter to an image filled with a solid grey color and then look at its histogram, you will see a classic bell-shaped Gaussian curve.)

The result is very naturally looking noise.

This filter does not work with indexed images.

Resultatet ser svært naturleg ut.

Filteret verkar ikkje på indekserte bilete.

4.3.2.  Options

Figure 15.69.  Scatter RGB” filter options

Scatter RGB filter options


This preview displays interactively changes before they are applied to the image.

Correlated noise

When checked, this radio button makes sliders R, G and B to move all together. The same relative noise will be added to all channels in each pixel, so the hue of pixels does not change much.

Independent RGB

When this radio button is checked, you can move each RGB sliders separately.

Red, Blue, Green and Alfa Sliders

These slidebars and adjacent input boxes allow to set noise level (0.00 - 1.00) in each channel. Alpha channel is only present, if your layer holds such a channel. In case of a grayscale image, a Grey is shown instead of color sliders.

The value set by these sliders actually determine the standard deviation of the normal distribution of applied noise. The used standard deviation is a half of the set value (where 1 is the distance between the lowest and highest possible value in a channel).