Patent ID: 6400468
Filing Date: 2002-06-04
Classification: H04N

Abstract:
A system for obtaining at least one calibration profile for an image scanning apparatus, the system comprising:a light source; a calibration image having a surface illuminated by said light source; a detector to measure an intensity of light obtained from a plurality of points on said calibration image and to measure an intensity of light obtained from a dark image at said plurality of points; a first memory to store a first plurality of light intensity values measured by said detector at each of the points and also to store a plurality of black intensity values measured by said detector at each of said points to form a black calibration profile; and a smoothing module used: to smooth the plurality of light intensity values in the first memory so as form a calibration profile; to smooth the plurality of black intensity values in the first memory; and to employ extrapolation, filtering and multirate filtering, repeated a number of times, and decimation upon data of a subset of the plurality of points.