Patent ID: 7099047
Filing Date: 2006-08-29
Classification: H04N

Abstract:
1. An image scanner comprising: an image sensor for photoelectrically converting an optical image into image signals; a light source for projecting rays toward a scanning position; an image forming lens for forming an optical image on said image sensor from rays traveling through a transparent original or rays being reflected from a reflective original as placed in said scanning position, said image forming lens being changeable in magnification; a first storage medium for storing at least one of a plurality of sets of shading correction data prepared for a plurality of magnification steps of said image forming lens, one set for one magnification; a second storage medium for storing at least a second set of shading correction data which are prepared for a second one of said plurality of magnification steps of said image forming lens, and are not stored in said first storage medium; a data writing device that reads out said second set of shading correction data from said second storage medium and writes said second set of shading correction data on said first storage medium if said image forming lens is set at said second magnification step; and a shading correction device for correcting image signals from said image sensor with a set of shading correction data that are read out from said first storage medium in correspondence with the magnification used on picking up said image signals.