| ntsc2rgb - converts from YIQ to RGB colorspace |
RGB = ntsc2rgb(YIQ) |
| RGB |
| A RGB image (M x N x 3) in 0-1 range or a RGB colormap (M x 3) in 0-1 range |
| YIQ |
| A YIQ image (M x N x 3) in 0-1 range or a YIQ colormap (M x 3) in 0-1 range |
| 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 !
|
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);
|
| Ricardo Fabbri <rfabbri@if.sc.usp.br> |
| The latest version of the Scilab Image Processing toolbox can be found at |
| http://siptoolbox.sourceforge.net |
| rgb2ntsc, im2gray |