The disclosure is directed to techniques for automatic focus control. The
automatic focus control techniques prioritize focus of a camera based on
skin tone using a skin color detection approach which is intrinsically
image sensor-dependent. Sensor-dependent skin color detection to support
automatic skin tone prioritized focus control in a camera can enhance the
focus of people in the scene. The techniques may be especially useful in
digital video camera design, digital still photo camera design, and
sensor applications involving people tracking. Sensor-dependent skin
color detection is performed once a specific sensor is characterized by
taking several raw images of a standard color test target in controlled
illumination conditions. Sensor-dependent skin color detection can
provide high detection precision and reliability. With sensor-dependent
skin color detection, the focus of a camera can be automatically adjusted
to prioritize regions of an image containing skin tones.