Method of and arrangement for copying a colored original

US4492458A · kind A · utility

Assignee

• Agfa-Gevaert NV · BE

Inventors

• Horst Bickl · Pullach, DE
• Gunter Findeis · Sauerlach, DE
• Helmut Treiber · Munich, DE

Key dates

• Filing date: Sep 22, 1982
• Grant date: Jan 8, 1985
• Expiry date: Sep 22, 2002

Classification

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

Abstract

A method of copying a colored original involves measuring the transparency of localized regions of the original in each of the three primary colors. Three localized transparency ratios for each region are formed from the transparency values for the different colors. Three corresponding average transparency ratios for the original as a whole are computed from the localized transparency ratios. Each average transparency ratio is compared with a statistical average of similar ratios obtained from a large number of average originals. If an average transparency ratio of the original to be copied deviates from the corresponding statistical average by more than a predetermined amount, the number of each of the localized transparency ratios lying inside and outside of a predetermined range about the corresponding average transparency ratio of the original is counted. When the number outside of a predetermined range exceeds the number inside, a color dominant is assumed to be present in the original. Otherwise, a color tinge is assumed to be present. The original is copied using a correction factor which depends upon whether a color dominant or a color tinge is present. An alternative metho…