Systems and methods of optical proximity correction are disclosed. A preferred embodiment comprises a method of determining optical proximity correction, which includes providing a design for a lithography mask. The design comprises a layout for a material layer of a semiconductor device. A predicted wafer image producible by the design for the lithography mask is calculated, and an amount of error between a target image and the calculated predicted wafer image is measured over a plurality of pixels of the predicted wafer image. The plurality of pixels comprises a plurality of different sizes.