AUTOMATIC FOCUSING DEVICE

PROBLEM TO BE SOLVED: To focus on a subject satisfactorily if it has a plurality of different colors even though luminance components are the same, by obtaining independent evaluation value to each of three primary color signals of image signals. SOLUTION: After high frequency components are extract...

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Bibliographic Details
Main Author ITO YUJIRO
Format Patent
LanguageEnglish
Published 11.09.1998
Edition6
Subjects
ACCESSORIES THEREFOR
APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USINGWAVES OTHER THAN OPTICAL WAVES
APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FORPROJECTING OR VIEWING THEM
CINEMATOGRAPHY
ELECTRIC COMMUNICATION TECHNIQUE
ELECTRICITY
ELECTROGRAPHY
HOLOGRAPHY
OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
OPTICS
PHOTOGRAPHY
PHYSICS
PICTORIAL COMMUNICATION, e.g. TELEVISION
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Summary:PROBLEM TO BE SOLVED: To focus on a subject satisfactorily if it has a plurality of different colors even though luminance components are the same, by obtaining independent evaluation value to each of three primary color signals of image signals. SOLUTION: After high frequency components are extracted from a red signal R, a green signal G and a blue signal B by HPFs(high-pass filters) 302R, 302G, 302B, the signals R, G, B are made to be absolute values by an absolute value processing circuit 303R, 303G, 303B and all made positive data. Horizontal frame control signals are then multiplied by multiplying circuits 304R, 304G, 304B and made into absolute value high frequency components within evaluation frames. One peak value is held every line in the frame by each of line peak holding circuits 305R, 305G, 305B and added in a vertical direction in relation to the line in the evaluation frame by each of vertical integrating circuits 306R, 306G, 306B. The output signals are added by an adding circuit 307 to obtain the horizontal evaluation value. The evaluation value is therefore generated when different colors are adjacent even though the luminance components are the same, so that the excellent evaluation value can be obtained in case of a subject with a plurality of different colors.
Bibliography:Application Number: JP19970047933