Video image quality may be improved by correcting exposure levels and/or
enhancing contrast amounts on each frame. One or more of the following
phases may be implemented: skin-color model building, face detecting,
exposure level correcting, and contrast enhancing. In a described
implementation, each pixel of an image frame is re-exposed using a ratio
of contrast amount control variables (CACVs). More specifically, a pixel
may be converted to a corresponding light intensity using a first CACV,
and the corresponding light intensity may be reconverted to a pixel using
a second CACV to enhance the contrast and possibly reduce fuzziness of
the image frame. In another described implementation, a Gaussian
skin-color model is built for each image frame during runtime. The
Gaussian skin-color model is built with training pixels that are selected
responsive to a defined skin color range, which is created offline from
manually-selected skin pixels of multiple test sequences.