Title:
AUTOMATIC FOCUSING DEVICE
Document Type and Number:
Japanese Patent JP3555607
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To prevent the erroneous detection of a focal position due to a pseudo peak, and to appropriately focus on an object.
SOLUTION: An image component in a focusing estimation area is extracted by an automatic focusing control part 20 from an image signal obtained when a focusing lens 12 is positioned in a certain lens position. And a contrast value C is obtained by a contrast calculation part 22 based on the image component, then, the value C is imparted to a focusing control part 24. Besides, an edge number EN and an edge width centroid value EW are obtained by an edge calculation part 23 based on the image component, then, the edge number EN and the value EW are imparted to the focusing control part 24. Whether or not the focusing lens 12 is positioned near the focal position is judged by the focusing control part 24 based on the edge number EN and the edge width centroid value EW obtained from the edge calculation part 23, and in the case it is judged that the lens 12 is not positioned near the focal position, the lens position is not accepted as the focal position even in the case the contrast value C shows the peak.
Inventors:
Shinichi Fujii
Application Number:
JP2001364754A
Publication Date:
August 18, 2004
Filing Date:
November 29, 2001
Export Citation:
Assignee:
Minolta Co., Ltd.
International Classes:
G03B13/36; G02B7/28; G02B7/36; H04N5/232; H04N9/04; (IPC1-7): G02B7/28; G02B7/36; G03B13/36; H04N5/232; H04N9/04
Domestic Patent References:
| JP5219418A |
Attorney, Agent or Firm:
Shigeaki Yoshida
Yoshitake Hidetoshi
Takahiro Arita
Yoshitake Hidetoshi
Takahiro Arita