Hello everyone,
the problem is as follows:
I calcualted the first and second derivatives of an image (1024x1280 pixel) using imgrdarientxy.
[Gx,Gy] = imgradientxy(Bild);
[Gxx,Gxy] = imgradientxy(Gx);
[Gyx,Gyy] = imgradientxy(Gy);
Now i want to calculate the eigenvalues of the Hessian matrix, which consists of the second derivatives of the image.
Simply said it would look something like this.
HessianMatrix1 = [Gxx(1,1) Gxy(1,1); Gyx(1,1) Gyy(1,1)];
[V1,D1,W1] = eig(HessianMatrix1);
HessianMatrix2 = [Gxx(1,2) Gxy(1,2); Gyx(1,2) Gyy(1,2)];
[V2,D2,W2] = eig(HessianMatrix2);
...
HessianMatrix1281 = [Gxx(2,1) Gxy(2,1); Gyx(2,1) Gyy(2,1)];
[V1281,D1281,W1281] = eig(HessianMatrix1281);
And so on. Basically the eigenvalues of the Hessian matrix (the second derivatives) for every pixel.
Now I don't know how to do this for the whole matrices.
I tryed it with a for loop but it only calcualtes the eigenvalue and eigenvector for the last iteration. I think I did a mistake in how the values are saved but i don't know how to fix it.
for j=1:n
for i=1:m
HesseM = [Gxx(i,j) Gxy(i,j); Gyx(i,j) Gyy(i,j)];
[V,D,W] = eig(HesseM);
end
end
Does anybody know how to implement this, so that it calcualtes all the eigenvalues (and eigenvectors) for every combination.
Thanks a lot,
Antonio
