A new auto-focus sharpness function for digital and smart-phone cameras

Passive auto-focusing is a key feature in consumer level digital and smart-phone cameras and is used to capture focused images without any user intervention. This paper introduces a new sharpness function for achieving passive auto-focusing, where the image sharpness information is used to bring it into focus. A comparison is made between this introduced sharpness function and the commonly used sharpness functions in terms of accuracy and computation time. The results obtained indicate that the introduced sharpness function possesses a comparable accuracy while demanding less computation time.