Patent ID: 7536281

Claim:
A method for compensating for a contaminated calibration target used in calibrating a scanner having a plurality of sensor pixels, said method comprising: (a) scanning a calibration target to generate a respective plurality of calibration data samples for each sensor pixel of said plurality of sensor pixels; (b) for said respective plurality of calibration data samples associated with a current sensor pixel of said plurality of sensor pixels, removing any calibration data sample that corresponds to a region of calibration target contamination on said calibration target, leaving filtered calibration data samples; (c) determining a gain value for said current sensor pixel based on said filtered calibration data samples; (d) repeating acts (b) and (c) for a next sensor pixel of said plurality of sensor pixels until a respective gain value is determined for each of said plurality of sensor pixels; and (e) applying the determined gain values to said plurality of sensor pixels for use in subsequent image scanning by said scanner.