Methods of and circuit array for compensating variations induced by temperature strain and manufacture in CMOS video sensors

US6912003B1 · kind B1 · utility

Assignee

• Institute for Mikroelektronik · DE

Inventors

• Uwe Apel · Neckartailfingen, DE
• Ulrich Seger · Renningen, DE
• Heinz-Gerd Graf · Titisee, DE
• Udo Postel · Dresden, DE
• Hans-Jörg Schönherr · Zeitz, DE
• Armin Armbruster · Tuttlingen, DE

Key dates

• Filing date: Oct 30, 1997
• Grant date: Jun 28, 2005
• Expiry date: Oct 30, 2017

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04N25/76
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

A method and circuit for compensating variations induced by temperature, strain and manufacturing technology in CMOS video sensors. Using at least two reference CMOS sensors, held at the same temperature level as the CMOS video sensors to be compensated and which are not irradiated, two reference signals are generated whereof one corresponds to a reference dark value whilst the other one, in response to the application of an electric current, corresponds to a reference illumination value. The reference signals are amplified separately of each other. At least one correction value is stored in a memory unit for each CMOS video sensor point to be compensated, such that output signals corrected by FPN (=fixed pattern noise) will be obtained. The FPN-corrected output signals as well as the reference signals obtained are supplied to the A/D converter where the output signals of the CMOS video sensor are compensated and converted into digital signals.