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@adpoe
Created Sep 27, 2016
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Energy Function - Matlab
function [ energy_matrix ] = energy_image( image_matrix_input )
%ENERGY_IMAGE Computes the energy at each pixel in a matrix nxmx3 matrix
% Outputs a 2D-matrix containing energy equation outputs, of datatype DBL
% convert image to grayscale first
G = rgb2gray(image_matrix_input);
% convert to double
G2 = im2double(G);
% create X and Y filters
horizontal_filter = [1 0 -1; 2 0 -2; 1 0 -1];
vertical_filter = [1 2 1; 0 0 0 ; -1 -2 -1];
% using imfilter to get our gradient in each direction
filtered_x = imfilter(G2, horizontal_filter);
filtered_y = imfilter(G2, vertical_filter);
energy_matrix = zeros(size(G2,1), size(G2,2));
% compute the energy at each pixel using the magnitude of the x and y
% gradients: sqrt((dI/dX)^2+(dI/dY)^2))
for y = 1:size(G2, 1)
for x = 1:size(G2,2)
% calculate energy function
y_magnitude = filtered_y(y,x) ^ 2;
x_magnitude = filtered_x(y,x) ^ 2;
energy_output = sqrt( y_magnitude + x_magnitude );
% fill energy matrix with our calculation
energy_matrix(y,x) = energy_output;
end
end
end
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