% Author : Sasakthi Abeysinghe, Timothy Simpson
% Date   : 02/15/2006

function homography = GetHomography(points)
% homography = GetHomography(points)
% Gets the set of points and creates a homography mapping pointset 1 to
% pointset 2.

points = double(points);

% Trying to solve Ax = b
b = [-points(:, 3); -points(:, 4)];
A = [-points(:, 1), -points(:, 2), -ones(size(points, 1), 1), zeros(size(points, 1), 3), points(:, 1) .* points(:, 3), points(:, 2) .* points(:, 3);
     zeros(size(points, 1), 3), -points(:, 1), -points(:, 2), -ones(size(points, 1), 1), points(:, 1) .* points(:, 4), points(:, 2) .* points(:, 4) ];
x = A\b;
homography = [x(1), x(2), x(3); x(4), x(5), x(6); x(7), x(8), 1];