Hessian2Ddec

Compute eigenvalues and eigenvectors of the Hessian of 2D matrix as gray images.
The miniature is obtain by following code :
I = mat2gray(imread('cameraman.tif'));
[n, m] = size(I);
idx = (1:20:(n*m))';
[rows, cols] = meshgrid(1:m, 1:n);
[l, v] = Hessian2Ddec(I, 10, true);
figure; imshow(I); hold on;
quiver(cols(idx), rows(idx), v(idx + n*m*2), v(idx + n*m*3), 'b')