Digital color video camera with auto-focus, auto-exposure and auto-white balance, and an auto exposure system therefor which compensates for abnormal lighting
First Claim
1. In a color video camera having an image pickup device providing a video signal representing a scene in a field of view of the camera and which is sampled and digitized to provide a corresponding digital video signal;
- the combination of;
an optical detector comprising means for separating luminance and chrominance components from said digital video signal, auto-focus detection means for detecting signal levels of said luminance component and providing a focus detection signal, auto-exposure detection means for detecting signal levels of said luminance component and providing an exposure detection signal, auto-white-balance detection means for detecting signal levels of said luminance and chrominance components and providing therefrom white-balance detection signals, and serial input and output ports common to said auto-focus detection means, said auto-exposure detection means and said auto-white-balance detection means; and
system controlling means common to said auto-focus detection means, said auto-exposure detection means and said auto-white-balance detection means, said system controlling means receiving said focus detection signal, said exposure detection signal and said white-balance detection signals through said serial output port and providing control signals through said serial input port to said auto-focus, auto-exposure and auto-white-balance detection means.
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Accused Products
Abstract
A color video camera providing a digital video signal has an auto-focus detector, an auto-exposure detector and an auto-white balance detector formed as sections of an optical detector circuit which further has serial input and output ports common to the auto-focus, auto-exposure and auto-white balance detectors, and a system controller which is common to the auto-focus, auto-exposure and auto-white balance detectors and provides control signals therefor through the serial input port while receiving focus, exposure and white-balance detection signals through the serial output port from the respective detectors. Further, an improved exposure control system is provided which compensates for abnormal lighting conditions, such as, back-lighting or excessive front-lighting of the scene in the field of view of the camera.
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Citations
18 Claims
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1. In a color video camera having an image pickup device providing a video signal representing a scene in a field of view of the camera and which is sampled and digitized to provide a corresponding digital video signal;
- the combination of;
an optical detector comprising means for separating luminance and chrominance components from said digital video signal, auto-focus detection means for detecting signal levels of said luminance component and providing a focus detection signal, auto-exposure detection means for detecting signal levels of said luminance component and providing an exposure detection signal, auto-white-balance detection means for detecting signal levels of said luminance and chrominance components and providing therefrom white-balance detection signals, and serial input and output ports common to said auto-focus detection means, said auto-exposure detection means and said auto-white-balance detection means; and system controlling means common to said auto-focus detection means, said auto-exposure detection means and said auto-white-balance detection means, said system controlling means receiving said focus detection signal, said exposure detection signal and said white-balance detection signals through said serial output port and providing control signals through said serial input port to said auto-focus, auto-exposure and auto-white-balance detection means. - View Dependent Claims (2, 3, 4, 5, 6)
- the combination of;
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7. A video camera comprising:
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image pickup means having a light reception surface for providing a luminance signal corresponding to a light image projected on said surface; lens means for directing incident light onto said surface in the form of an image corresponding to a scene in the field of view of said lens means; exposure means for controlling the amount of said light incident on said surface; means for defining at least one exposure detection area of said surface; detector means for detecting levels and distribution of said luminance signal corresponding to each said exposure detection area; and control means for controlling said exposure means in accordance with an output of said detector means. - View Dependent Claims (8)
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9. A video camera comprising:
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image pickup means having a light reception surface for providing a luminance signal corresponding to a light image projected on said surface; lens means for directing incident light onto said surface in the form of an image corresponding to a scene in the field of view of said lens means; exposure means for controlling the amount of said light incident on said surface; means for defining a plurality of exposure detection areas corresponding to respective portions of said light reception surface; first detector means for detecting levels of said luminance signal corresponding to said exposure detection areas, respectively; second detector means for detecting distributions of said levels of the luminance signal corresponding to said exposure detection areas, respectively, as an indication of a lighting condition of said scene; control means for controlling said exposure means in response to said first detector means; and means for controlling positions and dimensions of said exposure detection areas relative to each other in response to said second detector means. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A video camera according to claim 19;
- wherein said means for defining a plurality of exposure detection areas is operative to selectively define first and second exposure detection areas which respectively correspond to central and peripheral portions of said light reception surface, or third and fourth exposure detection areas which respectively correspond to portions of said light reception surface extending thereacross one above the other; and
wherein said means for controlling positions and dimensions of said exposure detection areas selects said first and second areas when said second detector means detects distributions of said levels of the luminance signal which indicate back-lighting or excessive front-lighting of said scene, and selects said third and fourth areas when said second detector means detects distributions of said levels of the luminance signal which indicate normal front-lighting of said scene.
- wherein said means for defining a plurality of exposure detection areas is operative to selectively define first and second exposure detection areas which respectively correspond to central and peripheral portions of said light reception surface, or third and fourth exposure detection areas which respectively correspond to portions of said light reception surface extending thereacross one above the other; and
Specification