US 4,480,266 A · Method and apparatus for preventing generation of false color signals in color television cameras

Abstract

In a color television camera of the type in which the red and blue color component signals modulated spatially by color filters and generated from a pick up tube are demodulated by the technique of phase separation through the utilization of correlation in successive scanning lines, a method and apparatus are disclosed which prevent the occurrence of false color signals within the camera by suppressing color errors which occur at the vertical edge portions in the reproduced image on a picture screen of a color television reproducing apparatus. The gain of a color error detecting difference signal indicative of the positions of the vertical edge portions is adjusted by either one or both of red and blue color difference signals, to selectively vary the amount of suppression of the color signals in accordance with the hues. The prevention of a decrease in the color saturation, and the prevention of a green or magenta color error, are effected at the contours of yellowish colors at the boundaries of black and white areas in an image having a high contrast.

Claims14

Dependent claims

A method of preventing the occurrence of false color signals generated in a color television camera of the type in which at least two color components of a color image are spatially modulated within a pick up tube by color filter means, and the resulting modulated color signal is demodulated by utilizing a vertical correlation on a reproduced image thereby producing color signals, wherein the improvement comprises the steps of:

(1) delaying an unmodulated color image luminance indicative signal produced within said camera by one horizontal scanning period;
(2) combining said unmodulated signal and said delayed unmodulated signal derived by said step (1) to produce a difference signal indicative of the positions of color errors;
(3) combining said unmodulated signal with at least one of a plurality of demodulated color component signals to produce a color difference signal, adjusting the amplitude of said difference signal by said color difference signal and generating said amplitude adjusted difference signal as a control signal, within said camera;
and
(4) suppressing said color component signals in accordance with said control signal.

2 more elements

An apparatus for preventing the occurrence of flase color signals generated in a color television camera of the type in which at least two color components of a color image are spatially modulated within a pick up tube by color filter means and the resulting modulated color signal is demodulated by utilizing a vertical correlation on a reproduced image thereby producing color signals, comprising:

delay means for delaying an unmodulated color image luminance indicative signal produced within said camera by one horizontal scanning period;
subtracting means for producing a difference signal indicative of the difference between said unmodulated signal and an output signal from said delay means;
control signal generating means for combining said unmodulated signal with at least one of a plurality of demodulated color component signals to produce a color difference signal, for adjusting the amplitude of said difference signal by said color difference signal and for outputting said amplitude adjusted difference signal, within said camera;
and
gain control means responsive to the control signal from said control signal generating means to suppress said color signals.

2 more elements

Dependencies are inferred from the claim text.

Method and apparatus for preventing generation of false color signals in color television cameras

Life of this patent

Method and apparatus for preventing generation of false color signals in color television cameras

Life of this patent

Abstract

Claims14