A simple image segmentation example

//A simple image segmentation example
image = imread('jump.jpg');     % read image
% get image dimensions: an RGB image has three planes
% reshaping puts the RGB layers next to each other generating
% a two dimensional grayscale image
[height, width, planes] = size(image);
rgb = reshape(image, height, width * planes);
imagesc(rgb);                   % visualize RGB planes
colorbar on                     % display colorbar
r = image(:, :, 1);             % red channel
g = image(:, :, 2);             % green channel
b = image(:, :, 3);             % blue channel
threshold = 100;                % threshold value
imagesc(b < threshold);         % display the binarized image
threshold = 100;                % threshold value
imagesc(b < threshold);         % display the binarized image
% apply the blueness calculation
blueness = double(b) - max(double(r), double(g));
imagesc(blueness);              % visualize RGB planes
colorbar on                     % display colorbar
% apply thresholding to segment the foreground
mask = blueness < 45;
imagesc(mask);