Title:
AUTOMATIC FOCUSING DEVICE
Document Type and Number:
Japanese Patent JPH1188760
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide an automatic focusing device which can precisely execute an automatic focusing operation regardless of image pickup conditions. SOLUTION: An integrating circuit 9b and a focusing detection circuit 10 output a selection signal S1 when the number of areas where the levels of luminance signal Y are below a reference value exceeds a prescribed rate in each of plural areas of a screen. Thus, a selector circuit 8 switches its input to a high pass filter 6b whose cut-off frequency is higher than a regular case so that the evaluation value of the area is not used for focusing. Accordingly only components higher than the signal Y are extracted, are gain-upped and are integrated in an integrating circuit 9a. The focusing detection circuit 10 outputs a control signal CL so as to make an integrated value S1n maximum, and to drive the focus lens of a lens block 2.
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Inventors:
FUJIKAWA HIROFUMI
Application Number:
JP24113197A
Publication Date:
March 30, 1999
Filing Date:
September 05, 1997
Export Citation:
Assignee:
SANYO ELECTRIC CO
International Classes:
G02B7/28; H04N5/232; (IPC1-7): H04N5/232; G02B7/28
Attorney, Agent or Firm:
Fukami Hisaro (3 outside)