TWO DIMENSIONAL SIGNALS
Some 2D signals are $ \ \delta\left (\mathit{x}, \mathit{y}\right ) $,Rect$ \left (\mathit{x}, \mathit{y}\right ) $,Sinc$ \left (\mathit{x}, \mathit{y}\right ) $.One important property of 2D functions is that they are separable,when they are a product of two 1D signals.They are of the form :
$ \ \mathbf{f}\left (\mathit{x}, \mathit{y}\right )=\mathbf{g}\left (\mathit{x}\right )\mathbf{h}\left (\mathit{y}\right) $
Rect$ \left (\mathit{x}, \mathit{y}\right ) = \begin{cases} 1, & \mbox{if }|x|&|y|\mbox{ is less than 1} \\ 0, & \mbox{if }\mbox{ else} \end{cases} $
