Patent ID: 6462772
Filing Date: 2002-10-08
Classification: H04N

Abstract:
A method of scanning a film strip and establishing image frame-specific gain calibration settings for a film image scanner including a solid state image sensor including an array of photosites, the method comprising:obtaining and setting, in advance of commencing image scanning operation, an initial gain calibration profile for gain adjustment, on a photosite-by-photosite basis, of output signals from said array of photosites; obtaining, at substantially the same time as said initial gain calibration profile is set, a reference film Dmin value from at least one predetermined photosite aligned with a region of film pixels extending longitudinally of the film strip outside of image frame areas of the film; subsequently advancing the film strip to one or more image frames to be scanned; obtaining, for each frame to be scanned, a frame-specific Dmin value from said at least one photosite obtained from said region adjacent to each said image frame to be scanned; and setting a revised gain calibration profile for each image frame scan based on adjustment of said initial gain calibration profile in proportion to a difference between said reference Dmin value and said frame-specific Dmin value corresponding to the image frame to be scanned.