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| Image pickup apparatus |
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| Visible light and near infrared imaging device |
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| Noise reduction system for color television signal |
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| Video level control |
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| Ghost cancelling system that cancels ghosts from video signals with a transversal filter |
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| Appliance and method of using same having a send capability for stored data |
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| Noise suppression circuit for a video signal |
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White balance controller for an image pick-up apparatus including an abnormality detector
| Details |
Inventors: Takagi, Yasushi; Imaide, Takuya;
Assignee: Hitachi, Ltd. (Tokyo, JP)
Primary Examiner: Coles, Sr.; Edward L.
Assistant Examiner: Vu; Kim Yen
Attorney, Agent or Firm: Antonelli, Terry, Stout & Kraus
A white balance controller for an image pickup apparatus having an image pickup for providing an output indicative of an image, a color separator responsive to the output of the image pickup for producing a luminance signal and a plurality of color signals therefrom, gain controllers for controlling a gain of at least two color signals of the plurality of color signals separated by the color separator, and a color difference signal generator for generating color difference signals from at least one of a color signal and luminance signal. The white balance controller includes white/achromatic detection for detecting at least one of a white and achromatic portion within an image picked up by the image pickup in accordance with a least the color difference signals, and an abnormality detector for detecting an abnormality of white balance within the picked up image. The abnormality detector supplies an output thereof to an input of the white/achromatic detector and enables control of a gain of the gain controllers in accordance therewith for enabling white adjustment. |
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DETAILED DESCRIPTION It is therefore an object of the present invention is to provide a white balance controller for establishing a suitable range for white extraction by combining information about saturation of an object and the color temperature of lighting, or the state of adjusted white balance.
If is another object of the present invention to achieve an accurate white extraction at all times corresponding to changes in viewing conditions of the object imaged.
In accordance with a feature of the present invention, the range (hue, saturation) to be accepted as white is rendered adaptive to the color temperature of lighting or the controlled state of white balance.
According to another feature of the present invention, the range (density, brightness) to be accepted as white is rendered adaptive to luminance distribution over the imaged object or the like.
When the white extraction range is determined with respect to the initial state of achieved white balance, the range of saturation to be accepted as white is fixed at all times, but if a change in the color temperature for white or the like is taken into consideration, the range will change depending on the adjusted state or white balance.
For example, when the color temperature up to 10000.
degree.
K.
is established to be accepted as white with the initial state set at 5000.
degree.
K.
, if white balance is achieved at 8000.
degree.
K.
, then even 20000.
degree.
K.
will be accepted as white, and, conversely, the extraction range on the lower color temperature side will become narrower.
In view of this, the present invention enables shifting of the white extraction range according to the adjusted state of white balance.
More specifically, when white balance is achieved at a higher color temperature, for example, control is exercised such that the white extraction range is expanded in the direction of red (positive direction along the R-B axis) and the white extraction range is compressed in the direction of blue (negative direction along the R-B axis)
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Image Analysis 
