rgb2ntsc - Converts from RGB to YIQ colorspace
rgb2ntsc(RGB) converts an RGB image or colormap from RGB to YIQ 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. rgb2ntsc(RGB) uses the following operation to convert each RGB triplet:
! Y ! ! 0.299 0.587 0.114 ! ! R ! ! I ! = ! 0.596 -0.274 -0.322 ! * ! G ! ! Q ! ! 0.212 -0.523 0.311 ! ! B !
initial_dir = PWD; chdir (SIPDIR + 'images'); rgb = imread('tru.jpg'); // RGB colorspace, 0-1 range imshow(rgb); yiq = rgb2ntsc(rgb); // YIQ colorspace, 0-1 range yiq(:,:,2) = yiq(:,:,2) /4; // Decrease chromaticity yiq(:,:,3) = yiq(:,:,3) /4; rgb = ntsc2rgb(yiq); imshow(rgb); chdir(initial_dir);
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