During recent years several state space models concerning discrete 2-D systems (systems with two time parameters) have appeared in the litterature. These are used for example in image processing. To these models are attached the names of Attasi , Fornasini-Marchesini , Givone-Roesser , the first two models being special cases of the third. This is shown in .
In this paper it is shown that all these models are special cases of a new model which is a straightforward generalization of the 1-D case.