Abstract: This paper addresses the representation of gray scale images by means of binary mathematical morphology, a relatively new nonlinear theory for image processing, based on set theory. The new image representation described in this work, called ``two steps" skeleton representation, is a extension of the morphological binary skeleton. This article will present the theoretical background of the morphological image representation and will show an application for gray scale images. At the end, the possibility to generalize the ``two steps" skeleton representation for multi-dimensional images will be analyzed, to extend the scope of its algebraic characteristics as much as possible. The application of the ``two steps" skeleton representation is illustrated by computer simulations.
Key words: Image coding, gray scale image, skeleton, morphology, multi dimensional image.