An image brightness and contrast management module for automatically
adjusting brightness and contrast of an input video signal includes a
histogram generation unit that generates a pixel luminance histogram
based on pixel luminance values in a frame, whereby the histogram shows a
distribution of luminance values in the frame and indicates the dynamic
range and the dominant luminance value(s) for the frame. The module
includes a histogram characterization unit that uses the pixel luminance
histogram to identify which of a plurality of brightness/contrast
properties is exhibited in the frame. The module also includes a
brightness and contrast adjustment unit that nonlinearly adjusts, in
real-time, the pixel luminance values in a next frame based on the
identified brightness/contrast properties exhibited in the preceding
frame. In this manner, bright or dark dominant areas of an image are
stretched to enhance the contrast of the dominant luminance values
without blackening the darker portions or saturating the brighter
portions of the image.