A NOVEL AUTOMATIC GAIN CONTROL METHOD FOR IMAGE INPUT TERMINALS
Original Publication Date: 1982-Feb-28
Included in the Prior Art Database: 2004-Apr-04
Xerox Disclosure Journal
Image Input Terminals (IITs) using Charged Coupled Devices (CCDs) typically employ some method of gain control to compensate for varying illumination, video amplifier drift, and unit-to-unit variations. In addition, the documents to be scanned may exhibit a high degree of variation in the effective background optical density, (e.g., colored paper). There is described herein an approach which will enable an IIT to automatically adapt to these variables in order to accurately scan an input document.