Camera auto focus system with detector circuits for generating evaluation functions

摘要

A method and apparatus for automatically focusing cameras. An auto focus circuit detects highly bright objects contained within an image frame of a scene. If highly bright objects are not detected, an auto focus processor adjusts the focus of the camera to maximize high spatial frequency components of the image frame. The auto focus processor focuses on the highly bright objects by minimizing a count function that indicates the number of pixels having greater magnitude than a threshold reference.