MATLAB: How to split a color image into its 3 RGB channels

recombine separate into rgb image againrgbseparate rgb channels

Hi,
How can I split a color image into its 3 RGB channels, like in this link:
http://www.originlab.com/www/products/images/ChannelSplit_Merge.png
Thanks

Best Answer

You can do that with this code:
% Read in original RGB image.
rgbImage = imread('flower.png');
% Extract color channels.
redChannel = rgbImage(:,:,1); % Red channel
greenChannel = rgbImage(:,:,2); % Green channel
blueChannel = rgbImage(:,:,3); % Blue channel
% Create an all black channel.
allBlack = zeros(size(rgbImage, 1), size(rgbImage, 2), 'uint8');
% Create color versions of the individual color channels.
just_red = cat(3, redChannel, allBlack, allBlack);
just_green = cat(3, allBlack, greenChannel, allBlack);
just_blue = cat(3, allBlack, allBlack, blueChannel);
% Recombine the individual color channels to create the original RGB image again.
recombinedRGBImage = cat(3, redChannel, greenChannel, blueChannel);
% Display them all.
subplot(3, 3, 2);
imshow(rgbImage);
fontSize = 20;
title('Original RGB Image', 'FontSize', fontSize)
subplot(3, 3, 4);
imshow(just_red);
title('Red Channel in Red', 'FontSize', fontSize)
subplot(3, 3, 5);
imshow(just_green)
title('Green Channel in Green', 'FontSize', fontSize)
subplot(3, 3, 6);
imshow(just_blue);
title('Blue Channel in Blue', 'FontSize', fontSize)
subplot(3, 3, 8);
imshow(recombinedRGBImage);
title('Recombined to Form Original RGB Image Again', 'FontSize', fontSize)
% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0, 0, 1, 1]);
% Get rid of tool bar and pulldown menus that are along top of figure.
% set(gcf, 'Toolbar', 'none', 'Menu', 'none');
% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off')
My MATLAB code produces this figure:
which you can see is the same as your example figure you gave:
The original flower image is attached. I cropped it out of your figure.
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