prgb2ast

Converts rgb color image to AST color image.

Synopsis

prgb2ast [-m mask] [im_in|-] [im_out|-]

Description

prvb2ast converts color image from the color space RGB (Red, Green, Blue) to the color space AST.

AST is the color space defined by Chassery. It is a simplified model based on the components:

    log(R) + log(V) + log(B)
A = ------------------------
             3
C₁ = sqrt(3)/2 * (log(R)-log(G))
C₂ = log(B) - 1/2*(log(R)+log(G))

A is an achromatic component and C1 and C2 is two chromatic components. From the model, it is possible to compute the hue h and the saturation s:

s = sqrt(C1²+C2²)
h = acos(C1/s)

Inputs

im_in: a RGB color image.

Outputs

im_out: a AST color image.

Result

Returns SUCCESS or FAILURE.

Examples

   prgb2ast parrot.pan a.pan

C++ prototype

Errc PRGB2AST( const Imc2duc &im_in, Imc2duc &im_out );

Version française

Changement d'espace couleur de RGB vers AST.

Reference

Reference: J.M. Chassery, "An iterative segmentation method based on a contextual color and shape criterion", IEEE Trans. Pattern Analysis and Machine Intelligence, Vol. 6, No. 6, pp 794-800, 1984.

Author: Olivier Lezoray