Implementation of a passive automatic focusing algorithm for digital still camera

A passive AF algorithm for the digital still camera is proposed. As a class of hybrid processing techniques, the proposed algorithm utilizes the two different focus measures by which the best focused image is extracted via two stages. With the paraxial geometric optics model of image formation, some well-known focus measures are investigated and a robust focusing algorithm is designed based on them. The proposed algorithm has been successfully tested on a prototype digital still camera.< >