SIP Toolbox

ntsc2rgb - Converts from YIQ to RGB colorspace

Calling Sequence

RGB = ntsc2rgb(YIQ)

Parameters

Description

ntsc2rgb(YIQ) converts an YIQ image or colormap from YIQ to RGB colorspace. The YIQ model is used in NTSC and European TV's. It is useful for b&w and color compatibility, since the cromaticity (I and Q) and luminance (Y) are conveniently isolated. ntsc2rgb(YIQ) uses the following operation to convert each YIQ triplet:

        ! R !   !  1.000  0.956    0.621   !   ! Y !
        ! G ! = !  1.000  -0.272   -0.647  ! * ! I !
        ! B !   !  1.000  -1.105   1.702   !   ! Q !
   

Examples

       initial_dir = PWD;
       chdir (SIPDIR + 'images');

       rgb = imread('tru.jpg');    // RGB colorspace 0-1
       imshow(rgb);
       yiq = rgb2ntsc(rgb);        // YIQ colorspace 0-1
       yiq(:,:,2) = yiq(:,:,2) /4; // Decrease chromaticity
       yiq(:,:,3) = yiq(:,:,3) /4;
       rgb = ntsc2rgb(yiq);
       imshow(rgb);

       chdir(initial_dir);
   

Authors

Ricardo Fabbri <ricardofabbri (AT) users DOT sf DOT net>

Availability

The latest version of the Scilab Image Processing toolbox can be found at

http://siptoolbox.sourceforge.net

See Also

rgb2ntsc,  im2gray,