An image analysis method is presented which effectively describes the
shape of a convex or concave particle. The method uses the Fourier des
criptors evaluated from the Fourier series expansion of the angular be
nd of the periphery of a particle as a function of its are length. The
Fourier descriptors are then used as inputs to unsupervised or superv
ised artificial neural networks to cluster and classify particles acco
rding to their shape. A number describing the class of a single partic
le or the average class of a population of particles can therefore be
deduced to characterize them.