EXPOSURE CONTROL METHOD, EXPOSURE CONTROL APPARATUS AND IMAGE PICKUP APPARATUS
First Claim
1. An exposure control method of an image pickup apparatus having an XY address scanning type imaging element, the method comprising the steps of:
- integrating a video signal obtained by shooting a subject by means of the imaging element as input video signal over not less than a horizontal period;
normalizing an integral value obtained in the integrating step or the difference value between integral values of adjacent fields or frames;
extracting flicker spectrum from the normalized integral value or the normalized difference value;
determining, based on the extracted flicker spectrum, the presence or absence of a flicker component contained in the video signal obtained by the imaging element; and
controlling an exposure value, using a program diagram for preferentially employing a shutter speed less liable to produce flickering when it is determined that the video signal contains a flicker component.
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Abstract
A technique of acquiring a width obtaining an appropriate exposure with minimum restrictions, while accurately correcting flickering is provided. An exposure control method includes integrating a video signal obtained by shooting a subject by means of a CMOS imaging element as input video signal over not less than a horizontal period, normalizing the integral value or the difference value of the integral value between neighboring fields or frames, extracting the integral value or the difference value after the normalization as flicker spectrum, determining, based on the extracted flicker spectrum, the presence or absence of a flicker component contained in the video signal obtained by the imaging element and controlling the exposure value, using a program diagram for preferentially employing the shutter speed less liable to produce flickering when it is determined that the video signal contains a flicker component.
85 Citations
15 Claims
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1. An exposure control method of an image pickup apparatus having an XY address scanning type imaging element, the method comprising the steps of:
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integrating a video signal obtained by shooting a subject by means of the imaging element as input video signal over not less than a horizontal period;
normalizing an integral value obtained in the integrating step or the difference value between integral values of adjacent fields or frames;
extracting flicker spectrum from the normalized integral value or the normalized difference value;
determining, based on the extracted flicker spectrum, the presence or absence of a flicker component contained in the video signal obtained by the imaging element; and
controlling an exposure value, using a program diagram for preferentially employing a shutter speed less liable to produce flickering when it is determined that the video signal contains a flicker component. - View Dependent Claims (2, 3, 4)
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5. An exposure control apparatus of an image pickup apparatus having an XY address scanning type imaging element, the apparatus comprising:
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flicker determining means for integrating a video signal obtained by shooting a subject by means of the imaging element as input video signal over not less than a horizontal period, normalizing an integral value obtained by integrating the video or the difference value between integral values of adjacent fields or frames, extracting flicker spectrum from the normalized integral value or the normalized difference value, and determining, based on the extracted flicker spectrum, the presence or absence of a flicker component contained in the video signal obtained by the imaging element; and
exposure value controlling means for controlling an exposure value, using a program diagram for preferentially employing a shutter speed less liable to produce flickering when it is determined by the flicker determining means that the video signal contains a flicker component. - View Dependent Claims (6, 7, 8)
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9. An image pickup apparatus comprising:
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an XY address scanning type imaging element;
flicker determining means for integrating a video signal obtained by shooting a subject by means of the imaging element as input video signal over not less than a horizontal period, normalizing an integral value obtained by integrating the video or the difference value between integral values of adjacent fields or frames, extracting flicker spectrum from the normalized integral value or the normalized difference value, and determining, based on the extracted flicker spectrum, the presence or absence of a flicker component contained in the video signal obtained by the imaging element from the extracted flicker spectrum; and
exposure value controlling means for controlling an exposure value, using a program diagram for preferentially employing a shutter speed less liable to produce flickering when it is determined by the flicker determining means that the video signal contains a flicker component. - View Dependent Claims (10, 11, 12, 13)
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14. An exposure control apparatus of an image pickup apparatus having an XY address scanning type imaging element, the apparatus comprising:
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a flicker determining unit configured to integrate a video signal obtained by shooting a subject by means of the imaging element as input video signal over not less than a horizontal period, normalize an integral value obtained by integrating the video or the difference value between integral values of adjacent fields or frames, extract flicker spectrum from the normalized integral value or the normalized difference value, and determine, based on the extracted flicker spectrum, the presence or absence of a flicker component contained in the video signal obtained by the imaging element from the extracted flicker spectrum; and
an exposure value controlling unit configured to control an exposure value, using a program diagram for preferentially employing a shutter speed less liable to produce flickering when it is determined by the flicker determining unit that the video signal contains a flicker component.
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15. An image pickup apparatus comprising:
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an XY address scanning type imaging element;
a flicker determining unit that integrates a video signal obtained by shooting a subject by means of the imaging element as input video signal over not less than a horizontal period, normalizes an integral value obtained by integrating the video or the difference value between integral values of the adjacent fields or frames, extract flicker spectrum from the normalized integral value or the normalized difference value, and determines, based on the extracted flicker spectrum, the presence or absence of a flicker component contained in the video signal obtained by the imaging element from the extracted flicker spectrum; and
an exposure value controlling unit configured to control an exposure value, using a program diagram for preferentially employing a shutter speed less liable to produce flickering when it is determined by the flicker determining unit that the video signal contains a flicker component.
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Specification