Dual directional microphone video camera having operator voice cancellation and control
First Claim
1. A video camera including an optical system and capturing a video image of a subject comprising:
- a first directional microphone having a directivity toward the subject, collecting sounds developed by the subject and converting the sounds into a first sound signal;
a second directional microphone having a directivity oriented generally toward an operator, collecting sounds from the operator and converting the sounds into said second sound signal;
sound generating means, operatively connected to said first and second directional microphones, for generating a third sound signal based on a difference between said first signal and said second signal; and
recording means, operatively connected to said sound generating means, for recording said third sound signal and for recording image data;
wherein said sound generating means includes,a first envelope detecting circuit for detecting the envelope of the first sound signal,a second envelope detecting circuit for detecting the envelope of the second sound signal,subtractor means for subtracting an output of said second envelope detecting circuit from an output of said first envelope detecting circuit to output a gain control signal, anda gain control circuit modifying the level of said first sound signal in dependence on said gain control signal.
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Abstract
A one-piece type video camera comprises a device for taking the image of a subject, a device for collecting the voice and a device for magnetically recording the image and voice, all of which are built in the camera as one piece. The voice collecting device includes a microphone for collecting the voice incoming from the subject and another microphone for collecting the operator'"'"'s voice. The operator'"'"'s voice is subtracted from the voice incoming from the subject such that only the latter will be recorded. The operator'"'"'s voice is utilized in the voice recognition technique so as to control the entire system of the video camera. In a preferred embodiment, the microphones are directional microphones.
62 Citations
15 Claims
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1. A video camera including an optical system and capturing a video image of a subject comprising:
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a first directional microphone having a directivity toward the subject, collecting sounds developed by the subject and converting the sounds into a first sound signal; a second directional microphone having a directivity oriented generally toward an operator, collecting sounds from the operator and converting the sounds into said second sound signal; sound generating means, operatively connected to said first and second directional microphones, for generating a third sound signal based on a difference between said first signal and said second signal; and recording means, operatively connected to said sound generating means, for recording said third sound signal and for recording image data;
wherein said sound generating means includes,a first envelope detecting circuit for detecting the envelope of the first sound signal, a second envelope detecting circuit for detecting the envelope of the second sound signal, subtractor means for subtracting an output of said second envelope detecting circuit from an output of said first envelope detecting circuit to output a gain control signal, and a gain control circuit modifying the level of said first sound signal in dependence on said gain control signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of recording sound with a video camera comprising the steps of:
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(a) producing a first signal from a first directional microphone; (b) producing a second signal from a second directional microphone, directed in a different direction than the first directional microphone; (c) detecting a first signal envelope; (d) detecting a second signal envelope; (e) generating a third signal by modifying the first signal in response to the difference between the detected first signal envelope and the detected second signal envelope; (f) recording the third signal in conjunction with an image. - View Dependent Claims (9, 10, 11, 14)
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12. A sound system for a camera including an optical system having an optical axis comprising:
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a first microphone pointed along the optical axis; a second microphone pointed away from said first microphone; a first envelope detector having an input from said first microphone; a second envelope detector having an input from said second microphone; a subtractor, having inputs from outputs of said first and second envelope detectors, and having a control signal as an output; an amplifier, amplifying an output of said first microphone in response to the control signal; and a recorder, recording the amplified output of said first microphone.
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13. A sound system for a video camera including an optical system having an optical axis comprising:
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a first microphone pointed along the optical axis and producing a first sound signal; a second microphone pointed away from said first microphone and producing a second sound signal; a first envelope detector receiving the first sound signal and determining the envelope thereof; a second envelope detector receiving the second sound signal and determining the envelope thereof; a gain control controlling the gain of the first sound signal in response to the difference between the first and second sound signals to produce a gain controlled first sound signal; and a recorder, recording the gain controlled first sound signal. - View Dependent Claims (15)
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Specification