Expanded-signal image enhancement system
AssigneeZenith Radio Corporation
InventorHoward F. Jirka
Life of this patent
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Abstract
A color television receiver includes well-known circuitry for detection and display of a received broadcast signal. Image enhancement means produce an expanded element luminance signal. A differentiating network produces the derivative of the expanded-element signal and a differential amplifier couples the derivative signal in a "push-pull" fashion to a pair of electrostatic deflection plates which influence the horizontal scansion of the receiver. A method of image enhancement as well as derivative processing and signal delay structures are shown.
Claims12
In a scanned display system in which an image is produced by scansion of a viewing screen in first and second directions, a method of image enhancement comprising the steps of:
- deriving an intensity control signal;
- applying said intensity control signal to said display system;
- producing an expanded-element intensity control signal having transition leading edges advanced with respect to those of said intensity control signal and transition trailing edges delayed with respect to those of said intensity control signal;
- differentiating said expanded-element intensity control signal to produce an image enhancement signal;
- and
- velocity modulating said first direction scansion with said image enhancement signal.
In a scanned display system in which an image, having an intensity responsive to an intensity control signal, is produced by scansion of a viewing screen in first and second directions, image enhancement means comprising:
- a source of intensity control signal;
- means coupling said intensity control signal to said display system;
- element expanding means, coupled to said source of intensity control signal, producing an expanded-element intensity control signal having transition leading edges advanced with respect to those of said intensity control signal and transition trailing edges delayed with respect to those of said intensity control signal;
- first differentiating means producing an image enhancement signal by differentiating said expanded-element intensity control signal;
- and
- arrest means modulating the scansion velocity of said display system in said first direction in response to said image enhancement signal.
In a television receiver having a cathode ray tube in which at least one electron beam is caused to scan the viewing screen thereof by synchronized horizontal and vertical deflection means, the intensity of said electron beam being controlled in part by a luminance signal;
- means enhancing the image produced on said viewing screen comprising:
- a source of luminance signal;
- means producing an image enhancement signal G(t) defined by the formula ##EQU1## where f(t) comprises said luminance signal, f'(t) comprises the first derivative of f(t) with respect to time and both a and b are constants;
- a pair of electrostatic deflection plates positioned relative to said electron beam such that the electric field therebetween influences said horizontal deflection;
- and
- means coupling said image enhancement signal to said deflection plates.
Dependencies are inferred from the claim text.