On constant luminance, gamma correction, and digitization of color space

Abstract

With one exception all color television standards, including proposed HDTV standards, violate the constant luminance principle by companding the RGB primaries. True luminance information is processed in the chroma channels. Visible luminance errors caused by processing and impairments in the chroma channels are reviewed and quantitatively analyzed. There is now a window of opportunity to develop digital TV standards without this well known flaw in TV color encoding. Digitization of color space and constant luminance proposals, including transmission of chromaticities, are examined. Further work leading to a constant luminance MPEG option, besides the linear option, is recommended.