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function myAffinityMat = Image2Graph (imIn)
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%Image2Graph produces a graph, in the form of a matrix, from an image
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% Usage myAffinityMat = Image2Graph (imIn), where:
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% Inputs
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% - imIn is the input image
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% Output
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% - myAffinityMat is the graph produced
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% Initializes helper variables
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imageWidth = size(imIn, 2);
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imageHeight = size(imIn, 1);
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imageChannels = size(imIn, 3);
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singleLineTransform = reshape(imIn, 1, [], imageChannels);
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% Calculates intensity difference per channel per point pair
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myAffinityMat = ...
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repmat(singleLineTransform, imageWidth * imageHeight, 1, 1) - ...
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permute(singleLineTransform, [2 1 3]);
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% Calculates "distance" between each point pair
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myAffinityMat = sum(myAffinityMat .^ 2, 3) .^ 0.5;
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% Calculates affinity between each point pair
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myAffinityMat = 1 ./ exp(myAffinityMat ./ var(imIn(:)));
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end
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