What are the Even and Odd Components of a 2D Signal
The even part of a 2D image $x[n,m]$ is defined as:

$$x_e[n,m] = \frac{x[n,m] + x[-n,-m] }{2} $$

and the odd part is
$$x_o[n,m] = \frac{x[n,m] - x[-n,-m] }{2} $$.