As in the case of 1-D signals, band limited images can be recovered
from periodic samples. Thus for example if the image 
is
low pass, that is to say that if
then
can be reconstructed by its samples taken every
units in the
direction and every
units in the
direction, and we can write
In image processing it is sometimes of greater use to use sampling schemes involving tesselations of the plane which are not rectangular such as hexagonal or triangular, when the low pass constraints have some circular symmetry.