Retinex Theory for Image Enhancement

Recorded color images differ from direct human viewing by the lack of dynamic range compression and color constancy. Research is summarized which develops the center/surround retinex concept originated by Edwin Land through a single scale design (SSR) to a multi-scale design with color restoration (MSRCR). The MSRCR synthesizes dynamic range compression, color constancy, and color rendition and, thereby, approaches fidelity to direct observation.

A computation for color images that approaches fidelity to scene observation must combine dynamic range compression, color consistency-a computational analog for human vision color constancy-and color and lightness tonal rendition. We refer to the computational analog to human vision color constancy as color consistency. When the dynamic range of a scene exceeds the dynamic range of the recording medium, there is an irrevocable loss of visual information at the extremes of the scene dynamic range.