I take part in a lesson of Automatic Image Analysis in this semester. And the first exercise is really interesting, so I decide to paste it here.
The two images in the left show two type of leaves that we want to identify in the right-up image, and the right-down image is the result of my algorithm.
The algorithm just need a so called Fourier Descriptor to finish the job and actually some morphology operators to find out the edges of each leaf.
My document(PDF format) of this task is below, if you have interest, maybe you can read it.
Homework 1. of Automatic Image Analysis – Fourier Descriptor