Exposure adjustment of an image using G+/G- curve

摘要

An improved exposure adjustment technique for brightening and darkening an image using a modified Gamma-like (G+) function is provided. The G+ function possesses characteristics such that, when applied brightening an image, the darker pixels are not enhanced too quickly when brightening, and the lighter pixels are not decreased too quickly when darkening. Two pertinent characteristics include the fact that the slope of the G+ function is not infinite at the origin, where “origin” corresponds to black pixels, and the slope near the origin, where corresponding to pixels are relatively dark, is lower than the slope of a conventional Gamma-like function.