Patent ID: 8643766

Claim:
An autofocus (AF) system, comprising: an autofocus device which controls focusing of an imaging optical system that forms a subject image on an imaging device so as to bring into focus a subject inside an AF area corresponding to position, size, and shape of an AF frame in a range of the subject that is imaged by the imaging device; a face recognition processing device which uses certification data showing features of a face of a specific person that is previously stored to detect an image of the face of the specific person in a captured image obtained by the imaging device; an object tracking device which sequentially detects a range of an image that matches an image of an arbitrary object within captured images that are sequentially obtained by the imaging device, and tracks the image of the object by means of an AF frame by setting the range as the AF area; and a face recognition and tracking device that updates the AF area, which is set by the face recognition processing device, at predetermined time intervals after setting the range of the image of the face of the specific person detected by the face recognition processing device as the AF area, while the object tracking device tracks an image in the set AF area as the image of the arbitrary object with the AF frame; wherein setting of the AF frame by the face recognition processing device is repeatedly performed every predetermined time interval and tracking of the object by the AF frame is performed multiple times during the predetermined time interval following an initial setting of the AF frame and prior to a subsequent setting of the AF frame.