Patent ID: 6806980
Filing Date: 2004-10-19
Classification: H04N

Abstract:
A method of correcting illumination variation in a scanned image of a non-planar original object, said method comprising:scanning at least a portion of the non-planar original object to produce scanned image data; acquiring illumination variation data from the scanned image data; deriving a plurality of illumination compensation values from the acquired illumination variation data; altering the scanned image data in accordance with the illumination compensation values, wherein the step of deriving a plurality of illumination compensation values includes: defining a background illumination distribution and a foreground illumination distribution; determining a background low threshold value BL and a background high threshold value BH from each background illumination distribution; determining a foreground low threshold value FL and a foreground high threshold value FH from each foreground illumination distribution; and calculating reference values for BL, BH, FL, and FH, from the plurality of determined BL, BH, FL, and FH values.