Abstract: A method and system for automatically calibrating a masking process simulator are disclosed. The method and system include performing a masking process using a calibration mask and process parameters to produce a calibration pattern on a wafer. A digital image is created of the calibration pattern, and the edges of the pattern are detected from the digital image using pattern recognition. Data defining the calibration mask and the process parameters are then input to a process simulator to produce an alim image estimating the calibration pattern that would be produced by the masking process. The method and system further include overlaying the alim image and the detected edges of the digital image, and measuring a distance between contours of the pattern in the alim image and the detected edges.