Abstract
We address the size of space-invariant patches in a large-field-of-view diffraction-limited imaging system. Given the coordinates of a point in the image plane, we derive the size of the space-invariant patch around it. Rather than in conventional radial and tangential directions, the size is calculated and expressed in the same rectangular coordinates as those of the image point. The presented formulas to calculate the size of the space-invariant patches are convenient to use to divide the space-variant large field of view field into the numbers of space-invariant fields. ©