Patent ID: 7571423

Claim:
A computer apparatus, comprising: at least one processor; at least one memory; and at least one program module, the program module stored in the memory and configured to be executed by the processor, the at least one program module including: instructions for providing a function having input values corresponding to an area of a photomask and output values indicating the position of a contour of a photomask pattern on the photomask, wherein the photomask pattern includes a number of different regions having different optical properties, the function results in at least three different output values over the area of the photomask, and the number of the different output values over the area of the photomask is greater than the number of different regions having the different optical properties; instructions for evaluating the function over at least a portion of the area of the photomask; and instructions for storing the output values from the function to represent the position of the contour of the photomask pattern over the portion of the area of the photomask, wherein the contour of the photomask pattern is adapted for use in subsequent fabrication of the photomask, wherein the instructions for storing the output values further include instructions for storing selected output values based on a distance to the contour of the photomask pattern.