Color space conversion in the analog domain

US7812870B2 · kind B2 · utility

Assignee

• Digital Imaging Systems GmbH · DE

Inventors

• Hubert Utz · Gilching, DE
• Detlef Schweng · Waiblingen, DE

Key dates

• Filing date: Jun 22, 2004
• Grant date: Oct 12, 2010
• Expiry date: Jan 12, 2028

Classification

• Technology area (CPC H): Electricity
• CPC primary: H04N25/135
• WIPO field: Audio-visual technology
• WIPO sector: Electrical engineering

Abstract

Systems and related methods have been achieved to convert in an analog domain the output of color image sensors into another color space. A chosen implementation converts the output of red, green, blue and white image sensors to the YcrCb color space, wherein the white image sensors are either extended dynamic range (XDR) image sensors or are of the same type as the other image sensors but have a larger size. The output of the white pixels can be used without conversion directly for the luminance Y value, thus achieving a very simple method for a conversion to YCbCr color space. Analog amplifiers, assigned to each of the red, green, and blue image sensors, have a gain according to the matrix describing the conversion from RGB to CbCr. Analog adders, assigned to Cb and Cr are adding the coefficients required for the computation of Cb and Cr. Finally the values of Y, Cb and Cr are converted to digital values. White pixels are advantageous but not required using the present invention. The present invention is also applicable for conversion to other color spaces as e.g. YIQ, YUV, CMYK, HIS, HSV, etc.