Autofocus control method
First Claim
1. An autofocus control method for adjusting a position of a lens to bring the subject of interest into focus, comprising the steps of:
- providing an arrangement wherein a ring-like region excluding a central region from an image pickup area is set up as a preset focus area for judgment of the degree of in-focus;
acquiring an image signal through the lens and an image pickup part;
calculating, based on the image signal thus acquired, a contrast value indicating the degree of in-focus of the preset focus area;
determining a lens position corresponding to a maximum contrast value as an in-focus lens position;
wherein, after autofocus processing is started, scene judgment is carried out to check whether or not the subject of interest is located at a near position with respect to a distant view;
wherein, if the result of scene judgment indicates that the subject of interest is not located at a near position with respect to the distant view concerned, the entire image pickup area is set up as a focus area, and focus adjustment is performed based thereon; and
wherein, if the result of scene judgment indicates that the subject of interest is located at a near position with respect to the distant view concerned, focus adjustment is performed based on the preset focus area.
1 Assignment
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Accused Products
Abstract
A ring-like region excluding a central region and a peripheral region from an image pickup area is preset as a focus area. An image signal is acquired through a lens and a CCD circuit. Based on the image signal thus acquired, a contrast value indicating the degree of in-focus of the preset focus area is calculated. A lens position corresponding to a maximum contrast value of the preset focus area is determined as an in-focus lens position. In autofocus processing, face detection is carried out first. Then, if the result of face detection is successful, a face region is set up as a focus area, and focus adjustment is performed based thereon. Alternatively, if the result of face detection is unsuccessful, focus adjustment is performed based on the preset focus area.
5 Citations
9 Claims
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1. An autofocus control method for adjusting a position of a lens to bring the subject of interest into focus, comprising the steps of:
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providing an arrangement wherein a ring-like region excluding a central region from an image pickup area is set up as a preset focus area for judgment of the degree of in-focus; acquiring an image signal through the lens and an image pickup part; calculating, based on the image signal thus acquired, a contrast value indicating the degree of in-focus of the preset focus area; determining a lens position corresponding to a maximum contrast value as an in-focus lens position; wherein, after autofocus processing is started, scene judgment is carried out to check whether or not the subject of interest is located at a near position with respect to a distant view; wherein, if the result of scene judgment indicates that the subject of interest is not located at a near position with respect to the distant view concerned, the entire image pickup area is set up as a focus area, and focus adjustment is performed based thereon; and wherein, if the result of scene judgment indicates that the subject of interest is located at a near position with respect to the distant view concerned, focus adjustment is performed based on the preset focus area. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification