Motion picture camera automatic focusing system
First Claim
1. A method of automatically focusing a camera, said method comprising the steps of(a) generating a first radio signal and transmitting the first radio signal from the camera to be focused toward a photographic subject;
- (b) responding to said first radio signal by generating a second radio signal and transmitting the second radio signal from the photographic subject;
(c) receiving the second radio signal at the camera;
(d) measuring the time interval between the transmittal of the first radio signal and the receipt of the second radio signal and generating a range signal that is representative of said measurement; and
(e) adjusting the focus of the camera in response to the range signal.
1 Assignment
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Accused Products
Abstract
A focusing system for a variable focus lens of a motion picture camera includes a pulse modulator and a microwave transmitter mounted on a camera frame for generating a high frequency pulsed signal which is transmitted to a selected target which carries a reactive signal generator that is responsive to the first signal for coding and retransmitting the coded signal back to a receiver mounted on the camera frame, and a signal processor for determining the interval of travel of the signal and translating the interval into a distance-analog signal that is transmitted to a focusing motor for driving the focusing mechanism of the lens for focusing the lens at the distance determined by the signal. One alternate embodiment includes multiple reactive signal generators having distinctive signal responsive controls and portable remote transmitters for selectively switching to the selected ones of said reactive generators. Another embodiment includes a system for synchronizing the controls of multiple cameras for preventing interference between them.
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Citations
16 Claims
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1. A method of automatically focusing a camera, said method comprising the steps of
(a) generating a first radio signal and transmitting the first radio signal from the camera to be focused toward a photographic subject; -
(b) responding to said first radio signal by generating a second radio signal and transmitting the second radio signal from the photographic subject; (c) receiving the second radio signal at the camera; (d) measuring the time interval between the transmittal of the first radio signal and the receipt of the second radio signal and generating a range signal that is representative of said measurement; and (e) adjusting the focus of the camera in response to the range signal. - View Dependent Claims (2, 3, 4)
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5. A system for automatically focusing a camera, said system comprising
first radio signal generating and transmitting means carried by the camera to be focused for generating and transmitting a first radio signal at a first frequency toward a photographic subject; -
second radio generating and transmitting means carried by the photographic subject and responsive to said first radio signal for generating and transmitting a second radio signal at a second frequency that is significantly higher than the first frequency; a microwave antenna carried by the camera for receiving the second radio signal and included in the first transmitting means for radiating the first radio signal; means for measuring the time interval between the transmittal of the first radio signal and the receipt of the second radio signal and for generating a range signal that is representative of said measurement; and means carried by the camera for adjusting the focus of the camera in response to the range signal. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12)
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13. A system for automatically focusing a camera having a predetermined lens, said system comprising
first radio signal generating and transmitting means carried by the camera to be focused for generating and transmitting a first radio signal toward a photographic subject; -
second radio generating and transmitting means carried by the photographic subject and responsive to said first radio signal for generating and transmitting a second radio signal; an antenna carried by the camera for receiving the second radio signal; means for measuring the time interval between the transmittal of the first radio signal and the receipt of the second radio signal and for generating an analog range signal that is representative of said measurement; and means carried by the camera for adjusting the focus of the camera in response to the range signal, the adjusting means comprising means for converting the analog range signal to a digital range signal; a digital memory for providing predetermined focusing signals for adjusting the focus of the predetermined lens in response to predetermined values of the digital range signal; and means responsive to the focusing signals for adjusting the focus of the camera lens. - View Dependent Claims (14, 15)
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16. A system for automatically focusing a camera, said system comprising
first radio signal generating and transmitting means carried by the camera to be focused for generating and transmitting a first radio signal toward a photographic subject; -
second radio generating and transmitting means carried by the photographic subject and responsive to said first radio signal for generating and transmitting a second radio signal; an antenna carried by the camera for receiving the second radio signal; means for measuring the time interval between the transmittal of the first radio signal and the receipt of the second radio signal and for generating a range signal that is representative of said measurement; means carried by the camera for adjusting the focus of the camera in response to the range signal; and means for maintaining the existing value of the range signal when no second radio signal is received between successive transmittals of the first radio signal.
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Specification