1.2. TWO-DIMENSIONAL SYSTEMS

In a two-dimensional system, the set of source two-dimensional functions displayed in a set of two-dimensional functions where - independent continuous spatial variables, the arguments of these functions . This mapping can be specified by a set of operators. at which link input and output functions:

(1.2.1)

Number of input functions may be more, less or equal to the number of days off. With

(1.2.2)

In one-dimensional physical systems in which time is an independent variable, the output signal is a function of past and non-valid values ​​of the input signal, but cannot be a function of future values. Such systems, called physically realizable, satisfy the causality principle. In general, two-dimensional systems do not have this property: spatial variables may take negative values ​​with respect to some origin.

To continue the discussion of the properties of two-dimensional systems, it is necessary to get acquainted with some special types of operators.