Autofocus system
View Patent ↗An autofocus system includes: an image pickup unit; an autofocus unit performing focus adjustment such that a subject in a AF area is to be in focus in the photographing image; a tracking unit moving the AF area to follow the movement of the subject in the range of the photographing image; a reference pattern registering unit registering the subject image in focus as a reference pattern; and a matched image detecting unit detecting a subject which is most closely matched with the reference pattern in the photographing image. When the amount of movement of the detected subject in a screen is less than a given value, the reference pattern is updated with the image of the subject, and an AF frame is updated to follow the moved subject. When the amount of movement is equal to or more than the given value, a tracking operation stops.
1. An autofocus system comprising:
an image pickup unit that takes an subject image formed by an optical system;
an autofocus unit that performs focus adjustment of the optical system so as to bring into an subject in a predetermined auto focusing (AF) area in each of photographing images taken by the image pickup unit;
a tracking unit that moves the AF area to follow a movement of the subject in a range of a photographing screen of the image pickup unit;
a reference pattern registering unit that registers as a reference pattern, an image of the subject which is to be in focus in the photographing images taken by the image pickup unit; and
a matched image detecting unit that detects an subject which is matched with the reference pattern in each of the photographing images taken by the image pickup unit,
wherein, when an amount of movement of the subject detected by the matched image detecting unit in the photographing screen of the image pickup unit is less than a given value, the reference pattern is updated with the image of the subject that is currently detected, and an AF frame is updated to follow the moved subject, and
when said amount of movement is equal to or more than the given value, the tracking unit stops a tracking operation.
2. The autofocus system according to claim 1 , wherein, when the tracking unit stops the tracking operation and thereafter the matched image detecting unit detects an image which is most closely matched with the reference pattern in the photographing image taken by the image pickup unit, the tracking unit resumes the tracking operation of an subject in the detected image.
3. The autofocus system according to claim 2 , wherein the given value varies depending on a panning/tilting operation of the image pickup unit.
4. The autofocus system according to claim 3 , wherein the image pickup unit takes photographing images with a predetermined period.
5. The autofocus system according to claim 1 , wherein the given value varies depending on a panning/tilting operation of the image pickup unit.
6. The autofocus system according to claim 1 , wherein the image pickup unit takes photographing images with a predetermined period.