genNoise

genNoise ( integer Input, integer Output, floating Sigma [ , integer Method =0 ] )

Use this function to generate noise and superimpose it on an image or selection. You can choose the desired type of the noise, its average intensity and density. If the image is a color one, the noise will be generated independently for each color component.

Parameters

Input

An integer between 0 and 116 specifying the input image frame number. A value of 0 represents the DMA memory buffer of the video device. Values in the range of 100-116 correspond to hidden frames.

Output

An integer between 1 and 116 specifying the output image frame number. Values in the range of 100-116 correspond to hidden frames.

Sigma

A positive floating variable or constant specifying the standard deviation ó for the statistical distribution of noise. The larger this value is, the bigger the noise variations will be.

Density

An enumerated integer that describes the type of the noise distribution. Must be on of the following values:

NS_UNIFORM – uniformly distributed white noise of the selected variance. The amplitude range of the noise is limited to the value of

NS_GAUSS – Gaussian white noise of the selected local variance. The intensity distribution of noise is defined by the following equation:

NS_EXPONENT – exponential white noise of the selected local variance. The intensity distribution of noise is defined by the following equation:

NS_POISSON – Poisson noise generated from the image data. The intensity distribution of noise is defined by the following equation:

Default value: NS_UNIFORM

Example

This set of statements continuously grabs an image and adds to it a uniform noise with the standard deviation 20:

do

grabim (100)

gennoise(100,1,20,0)

loop