One embodiment of the present invention provides a system that computes translational differentials between a “perfect” image (henceforth called a database-image) and a scanned-image of a photomask. During operation, the system receives a noise-free database-image and a scanned-image that is generated...http://www.google.com/patents/US7415150?utm_source=gb-gplus-sharePatent US7415150 - Photomask image registration in scanning electron microscope imagery
