APPARATUS, SYSTEM, AND METHOD FOR OPTIMIZING GAMMA CURVES FOR DIGITAL IMAGE DEVICES

摘要

An apparatus, system, and method provide optimization of color space conversion using a joint quality metric representing differences between reference human visual representations and converted device captured image representations in a perceptual uniform color space, where the conversion includes transforming a nonstandard color space (RGB) to a perceptual standard color space (sRGB) and where the joint quality metric includes a color portion, a noise portion, and a contrast portion. An optical sensor produces a digital reference signal when capturing an image of a reference source such as a Macbeth ColorChecker color rendition chart. After white balancing and color correcting the digital reference signal, the gamma curve parameters are determined by minimizing the joint quality metric which is based on differences, within a uniform perceptual color space such as CIELAB, between the gamma curve compensated signal and the standard values for the reference source. The noise portion and contrast portion take into account the noise and the contrast of the gamma curve compensated signal resulting in a gamma curve parameter that is optimized with respect to color, noise, and contrast.