An apparatus and method for performing automatic exposure and gain control
while minimizing oscillations as well as providing a good response time,
for example, a lag time or a settling time of about one frame. The
automatic exposure and gain controls are performed not only on the image
as a whole but on a weighted region of interest. If the contrast in the
image exceeds the dynamic range of the sensor array, then the image in
the region of interest will improve at the expense of the remainder of
the image. A region of interest is a selected subset of tiles upon which
automatic exposure and gain control will be based. The tiles are defined
by a grid system having grid coordinates, which are programmable. Image
sensors have to receive feedback with regular updates of exposure and
gain settings based on ever changing light conditions.