Automatic iris control for solid-stage imaging apparatus
First Claim
1. A solid-state imaging apparatus comprising:
- charge-coupled imaging means including an imaging area for generating charges responsive to light incident thereon, output means responsive to the charges generated in the imaging areas for producing an electrical output signal;
first means for obtaining a video information signal from said electrical output signal;
second means for obtaining a reference signal from said electrical output signal;
optical iris means for controlling the intensity of light incident upon at least a part of said imaging area;
first iris control means responsive to said video information signal for controlling said optical iris means and to said reference signal;
overflow detection means for detecting an overflow of charges from said imaging area; and
second iris control means responsive to the output of said overflow detection means for controlling said optical iris to lower said intensity of the light;
whereby, when there is not an overflow of charges from said imaging area, said optical iris is controlled by said first iris control means to maintain said intensity of the light to a proper value, and, when there is an overflow of charges from said imaging area, said optical iris is controlled by said second iris control means to lower the intensity of light and thereby prevent said overflow of charges.
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Accused Products
Abstract
An iris controls the amount of light transmitted through television camera lens to an integrated semiconductor matrix of light responsive elements. A characteristic of the matrix is that photo-charges may overflow the light responsive elements if the light falling on the matrix becomes too bright. The normal iris control responds to a loss of picture contrast caused by the overflow of charges and attempts to increase contrast by increasing the amount of light passing through the lens. The invention compares the output from the light responsive elements with a reference signal representing black areas in the picture. When the comparison exceeds a given difference, a special iris control overrides the normal iris control in order to reduce the amount of light passing through the lens. The reference signal may be taken from one or more of the light responsive elements which are shielded from light passing through the lens. Or, the reference signal may be taken during periods between picture frames when the video signal does not record any light.
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Citations
13 Claims
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1. A solid-state imaging apparatus comprising:
- charge-coupled imaging means including an imaging area for generating charges responsive to light incident thereon, output means responsive to the charges generated in the imaging areas for producing an electrical output signal;
first means for obtaining a video information signal from said electrical output signal;
second means for obtaining a reference signal from said electrical output signal;
optical iris means for controlling the intensity of light incident upon at least a part of said imaging area;
first iris control means responsive to said video information signal for controlling said optical iris means and to said reference signal;
overflow detection means for detecting an overflow of charges from said imaging area; and
second iris control means responsive to the output of said overflow detection means for controlling said optical iris to lower said intensity of the light;
whereby, when there is not an overflow of charges from said imaging area, said optical iris is controlled by said first iris control means to maintain said intensity of the light to a proper value, and, when there is an overflow of charges from said imaging area, said optical iris is controlled by said second iris control means to lower the intensity of light and thereby prevent said overflow of charges. - View Dependent Claims (2, 3)
- charge-coupled imaging means including an imaging area for generating charges responsive to light incident thereon, output means responsive to the charges generated in the imaging areas for producing an electrical output signal;
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4. A solid-state imaging apparatus comprising:
- a solid-state imaging means for generating a first signal relating to picture element information at a level corresponding to the quantity of incident light on said imaging means and for generating a second signal relating to reference information, said second signal having a level which is independent of the incident light;
optical system means for forming an image upon a surface of said solid-state imaging means;
optical iris means for controlling the quantity of the light incident upon said surface of said solid-state imaging means;
means for extracting a video signal from the output of said solid-state imaging means in accordance with said picture element information;
normal control means for controlling said optical iris means in accordance with said first signal; and
alternate control means for controlling said optical iris means to lower the quantity of the incident light when said second signal is higher than a present level. - View Dependent Claims (5, 6, 7)
- a solid-state imaging means for generating a first signal relating to picture element information at a level corresponding to the quantity of incident light on said imaging means and for generating a second signal relating to reference information, said second signal having a level which is independent of the incident light;
- 8. An imaging apparatus comprising an integrated semiconductor matrix of individual light responsive imaging areas which produce free charge carriers in quantities corresponding to the intensity of light incident to the individual areas, means for causing at least one of said imaging areas to produce charges in a quantity irrespective of light incident to said one area, means for comparing the quantity of charges produced in the imaging area in the presence of light with the reference quantity of charges produced irrespective of light, and means responsive to said comparing means for reducing the intensity of said light falling on said area when said comparing means detect quantities which exceed a given difference.
Specification