MATLAB: How would you create a mask on an image

image processing

I am doing a project and one of the tasks is to create a matrix with number of pixels x number of pixels x 3 as its size. In the previous task I created a matrix using the green container of the RGB image and I am suppose to duplicate this along the 3 dimensions. My question is what functions would I use in order to do this. I am not allowed to use any implicit functions only explicit.

Best Answer

Here's one method:
    % Multiply the mask by each color channel individually.
    maskedRed = redChannel .* mask;
    maskedGreen = greenChannel .* mask;
    maskedBlue = blueChannel .* mask;
    % Recombine separate masked color channels into a single, true color RGB image.
    maskedRgbImage = cat(3, maskedRed, maskedGreen, maskedBlue);
Here's another method, suggested by Sean D.
% Mask the image.
maskedRgbImage = bsxfun(@times, rgbImage, cast(mask,class(rgbImage)));
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