Video tracking system
First Claim
1. A video tracking system comprising:
- a television camera adapted to be trained upon an area of observation containing a target to be tracked;
a television receiver provided with a monitoring screen and connected to said camera for receiving therefrom an input signal to display on said screen a picture of said area of observation including an image of said target, said input signal including synchronizing pulses for controlling a periodic deflection of an electron beam in said receiver in two mutually orthogonal sweep directions;
window-generating means connected to said receiver for delineating on said screen a rectangular window with sides extending in said sweep directions, said window-generating means including a source of scanning voltage controlled by said synchronizing pulses and gating means for passing selected portions of said scanning voltage to said receiver;
manually operable acquisition means adapted to control said source for modifying said scanning voltage to align said window with a desired target image on said screen; and
tracking means connected between said camera and said source for keeping the energy center of said target image substantially coincident with the geometrical center of said window upon substantial alignment thereof by said acquisition means, said tracking means including a first pair of measuring circuits responsive to a first pair of timing pulses from said gating means for detecting the energy content of said input signal in respective halves of a beam sweep in one of said directions across said window, a second pair of measuring circuits responsive to a second pair of timing pulses from said gating means for detecting the energy content of said input signal in respective halves of a beam sweep in the other of said directions across said window, first comparison means connected to said first pair of measuring circuits for generating a first error signal proportional to a difference in said energy content on a beam sweep in said one of said directions, second comparison means connected to said second pair of measuring circuits for generating a second error signal proportional to a difference in said energy content on a beam sweep in said other of said directions, and circuitry for applying said error signals to said source for further modifying said scanning voltage.
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Accused Products
Abstract
The field observed by a video camera includes a desired target which is to be encompassed by an electronic window. The acquisition of the target is controlled initially by a light pen to position the electronic window on the target displayed on the screen of a receiver. Automatic video tracking proceeds then by measuring the mean video level in the vicinity of the target, adjusting the signal to this level and rectifying it, and then periodically measuring the difference in energy in the two successive halves of the window along the axis in question, this measurement giving the positional divergence between the center of the window and the energy center of the target. Corresponding error signals are used to move the window to keep the target centered therein.
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Citations
10 Claims
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1. A video tracking system comprising:
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a television camera adapted to be trained upon an area of observation containing a target to be tracked; a television receiver provided with a monitoring screen and connected to said camera for receiving therefrom an input signal to display on said screen a picture of said area of observation including an image of said target, said input signal including synchronizing pulses for controlling a periodic deflection of an electron beam in said receiver in two mutually orthogonal sweep directions; window-generating means connected to said receiver for delineating on said screen a rectangular window with sides extending in said sweep directions, said window-generating means including a source of scanning voltage controlled by said synchronizing pulses and gating means for passing selected portions of said scanning voltage to said receiver; manually operable acquisition means adapted to control said source for modifying said scanning voltage to align said window with a desired target image on said screen; and tracking means connected between said camera and said source for keeping the energy center of said target image substantially coincident with the geometrical center of said window upon substantial alignment thereof by said acquisition means, said tracking means including a first pair of measuring circuits responsive to a first pair of timing pulses from said gating means for detecting the energy content of said input signal in respective halves of a beam sweep in one of said directions across said window, a second pair of measuring circuits responsive to a second pair of timing pulses from said gating means for detecting the energy content of said input signal in respective halves of a beam sweep in the other of said directions across said window, first comparison means connected to said first pair of measuring circuits for generating a first error signal proportional to a difference in said energy content on a beam sweep in said one of said directions, second comparison means connected to said second pair of measuring circuits for generating a second error signal proportional to a difference in said energy content on a beam sweep in said other of said directions, and circuitry for applying said error signals to said source for further modifying said scanning voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification