Automatic recognition of complex images is a hard and computationally expen
sive task, mainly because it is extremely difficult to capture in an automa
tic way and with a few features the necessary discriminant information. If
such features were available, a proper learning system could be trained to
distinguish images of different kinds of objects, starting from a set of la
beled examples. In this paper we show that fractal features obtained from I
terated Function System encodings capture the kind of information that is n
eeded by learning systems and, thus, allow the successful classification of
2-dimensional images of objects. We also present a fractal feature extract
ion algorithm and report the classification results obtained on two very di
fferent test-beds by applying Machine Learning techniques to sets of encode
d images. (C) 2000 Academic Press.