Method of determining correction parameters for use in light-amount adjustment in a color copying operation

US4344704A · kind A · utility

Assignee

• Agfa-Gevaert NV · BE

Inventors

• Siegfried Thurm · Meerbusch, DE
• Konrad Bunge

Key dates

• Filing date: Jun 19, 1980
• Grant date: Aug 17, 1982
• Expiry date: Jun 19, 2000

Classification

• Technology area (CPC G): Physics
• CPC primary: G03B27/735
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A method of determining correction parameters for adjusting the amounts of light to which originals are to be exposed in a color copying operation in dependence on the composition deviations of the respective original from a calibrating original involves establishing, for each of a multitude of regions of the respective original, two characteristic values respectively representative of a relationship between the blue and green color values, on the one hand, and the red and green color values, on the other hand, averaging those of the established characteristic values the relationships of which are within a distribution range normally encountered in an image of an object on the original, forming an average from the average values, and ascertaining the magnitude and direction of the correction parameters from the difference between the average obtained from the particular original and a like average obtained from the calibrating original. The regions into which the original is subdivided are successively scanned and the scanned area of each region is only a small fraction of the total area of the respective region. The method may be performed on a single original or on a series of or…