Patent ID: 8237847

Claim:
An auto focus system, comprising: an auto focus unit that controls the focus of an imaging optical system which focuses an imaging unit on an object such that an object in a portion corresponding to an AF frame in the range of the object captured by the imaging unit is in focus; a face detecting unit that detects the image of a person's face from the image captured by the imaging unit; a pattern matching unit that detects the image of an object, which is a tracking target, from the image captured by the imaging unit, using a pattern matching process, on the basis of a reference pattern image that is stored as the image of the object, which is the tracking target; a first AF frame determining unit that, when the image of the person's face is included in the AF frame, determines the position of the AF frame in the image captured by the imaging unit on the basis of the position of the image of the face detected by the face detecting unit; a second AF frame determining unit that determines the position of the AF frame in the image captured by the imaging unit on the basis of the position of the image of the object, which is the tracking target, detected by the pattern matching unit; and an AF frame changing unit that is configured to perform during an auto-tracking process of the tracking target, wherein when one of the first AF frame determining unit and the second AF frame determining unit is set as a preferential AF frame determining unit, the AF frame changing unit changes the position of the AF frame to a position determined by the preferential AF frame determining unit, when the determination of the position of the AF frame by the preferential AF frame determining unit is unavailable, the AF frame changing unit changes the position of the AF frame to a position determined by one of the first AF frame determining unit and the second AF frame determining unit being not set as the preferential AF frame determining unit; and wherein different arithmetic processors separately perform the face detecting process and the pattern matching process, and the face detecting process and the pattern matching process are performed at the same time.