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EP0971534A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Automatic level control unit of camera

Assignee: Toshiba Corp
•
Filing: 1999-06-16
•
Granted: —
•
Expires: 2019-06-16
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Abstract

Abstract To provide an automatic level control unit of a camera that, even in the case of an area sensor that is not able to maintain simultaneity in one screen being employed, with a small size circuit, can prevent flicker of a fluorescent lamp from occurring, and implement a smooth level control of an automatic level control. In an automatic level control of a camera that controls an electronic shutter speed and a gain of an amplifier to be a prescribed output level by calculating the electronic shutter speed and the gain of an amplifier from the output level, when an object illuminance becomes low and the electronic shutter speed becomes lower than 1/(on/off frequency of a light source) second, the possible electronic shutter speed is restricted to integer times of 1/(on/off frequency of a light source) second, and at that time, a more finer level control than a level control range that the electronic shutter speed can control by integer times of 1/(on/off frequency of a light source) second is implemented by controlling the gain of the amplifier.

Inventors

  • 👤 Himio Yamauchi

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-09 12:03
CPC Classifications
H; H04; H04N; H04N23/00; H04N23/70; H04N23/72; H04N23/745; H04N23/76

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 75 words
An automatic level control unit of a camera that calculates an electronic shutter speed and a gain of an amplifier from an output level so that a prescribed output level is obtained after level control: wherein the electronic shutter speed is controlled by step adjustment, and the output level of the step after control of the electronic shutter speed is compensated by fine level control of the amplifier, thereby the output level is controlled smoothly.
Claim 2
Dependent Claim 116 words
An automatic level control unit of a camera that calculates an electronic shutter speed and a gain of an amplifier from an output level so that a prescribed output level is obtained after level control: wherein when an object illuminance becomes low and the electronic shutter speed becomes slower than 1/(on/off frequency of a light source) second, the possible electronic shutter speed is restricted to integer times of 1/(on/off frequency of a light source) second, and at that time, a more finer level control than a level control range that the electronic shutter speed can control by integer times of 1/(on/off frequency of a light source) second is implemented by controlling the gain of the amplifier.
Claim 3
Dependent Claim 42 words
The automatic level control unit of a camera as set forth in claim 2, further comprises: a means for detecting an on/off frequency of a light source; wherein the electronic shutter speed is controlled based on the result detected by the means.
Claim 4
Dependent Claim 109 words
An automatic level control unit of a camera that calculates an electronic shutter speed and a gain of an amplifier from an output level so that a prescribed output level is obtained after level control: wherein when an object illuminance becomes high and the electronic shutter speed becomes higher than a certain arbitrary speed, the possible electronic shutter speed is restricted to integer times of a certain arbitrary shutter speed, and at that time, a more finer level control than a level control range that the electronic shutter speed can control by integer times of the certain arbitrary shutter speed is implemented by controlling the gain of the amplifier.
Claim 5
Dependent Claim 97 words
The automatic level control unit of a camera as set forth in any one of claim 1 through claim 4: wherein an input of the amplifier is a digital signal after an A/D; and further comprises; an amplifier, an input of the amplifier being an analog signal before the A/D; and a gain control means for controlling a gain of the amplifier of which input is the analog signal to be an output of a prescribed level when, notwithstanding an object illuminance becomes low and the electronic shutter speed is the lowest, an output level is low.
Claim 6
Dependent Claim 97 words
The automatic level control unit of a camera as set forth in any one of claim 1 through claim 4: wherein an input of the amplifier is an analog signal before the A/D; and further comprises; an amplifier, an input of the amplifier being a digital signal after the A/D; and a gain control means for controlling a gain of the amplifier of which input is the digital signal to be an output of a prescribed level when, notwithstanding an object illuminance becomes low and the electronic shutter speed is the lowest, an output level is low.

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