[Harris] source code stackoverflow

clc;
clear;
close;

%grayImage = checkerboard(50);
grayImage = imread('IMG_20141225_001413.jpg');
grayImage = rgb2gray(grayImage);
grayImage = im2double(grayImage);
verticalMask = [-1 0 1;
            -2 0 2;
            -1 0 1]* 0.25;
% Create a mask for deteting the horizontal edges
horisontalMask = [-1 -2 -1;
              0 0 0;
              1 2 1]* 0.25;
% Create a mask for Gaussian filter(is used to improve the result)
gaussianFilter= fspecial('gaussian');
K = 0.04; % The sensitivity factor used in the Harris detection algorithm (Used to detect sharp corners).
% Get the gradient of the image [Ix,Iy], using the convulation function
Ix = conv2(grayImage,verticalMask);
Iy = conv2(grayImage,horisontalMask);

% get the input arguments of the harris formula
Ix2 = Ix.* Ix; % get Ix to the power of two
Iy2 = Iy.* Iy; % get Iy to the power of two
Ixy = Ix .* Iy; %get the Ixy by multiply Ix and Iy

% Apply the gaussian filter to the the arguments
Ix2 = conv2(Ix2,gaussianFilter);
Iy2 = conv2(Iy2,gaussianFilter);
Ixy = conv2(Ixy,gaussianFilter);

% Enetr the arguments into the formula
C = (Ix2 .* Iy2) - (Ixy.^2) - K * ( Ix2 + Iy2 ).^ 2;

thresh = 0.000999;
radius = 1;

% Find maxima, threshold, and apply bordermask
cimmx = (C>thresh);
[r, c] = find(cimmx);     % Return coordinates of corners

figure, imshow(grayImage);
hold on;
plot(c, r, '+');
hold off;