Hi Jacob your code is very helpful.
BTW I noticed two memory leaks.
One is in the implementation of GlTree, I will post in that FileExchange. The other is in the usage of inputParser. You should clear the object inp.
I think there is an error. The ratio of the eigenvalues is not always correct. They must ordered by their abs value before. In your implementation this is not true.
Second point : the normalized derivatives of Lindeberg. In the normalization you should use sigma^2 and not sigma. Maybe I am wrong but it is strange that the paper of Frangi (1998) contains the same error.