Patent ID: 7944545

Claim:
A method comprising: using at least provided information corresponding to a pattern to be printed on a substrate, determining a plurality of bright points at an image plane and a plurality of dark points at the image plane; generating a plurality of joint eigenvectors corresponding to the plurality of bright points and the plurality of dark points; selecting a number of the plurality of joint eigenvectors suitable to project the pattern as determined by at least one metric, the number of selected joint eigenvectors less than the number of the plurality of joint eigenvectors; generating a plurality of natural sampling points using the plurality of bright points and the selected joint eigenvectors, wherein each of the plurality of natural sampling points has a substantially equal intensity; using the plurality of generated natural sampling points to determine a plurality of possible solutions corresponding to masks suitable for printing the pattern on the substrate; selecting one of the possible solutions according to predetermined criteria as a best solution of the possible solutions for printing the pattern on the substrate; and outputting information corresponding to the selected solution, the information suitable for creating a mask suitable for printing the pattern on the substrate.