Automatic color balancing system
AssigneeRobert Bosch GmbH
InventorDieter Poetsch
Life of this patent
Estimating the term…
Abstract
A system for regulating the color balance of a television signal by storing hue values only during periods when a predetermined luminosity gradient is present in the picture while, simultaneously, the picture remains below a predetermined color saturation threshold, and by using the stored hue value during subsequent periods to derive a regulating signal for controlling a color corrector.
Claims17
A system for automatic correction of at least two color difference signals which determine the color and luminosity of a color television signal comprising:
- (A) first means responsive to said signal for providing a first indication when a predetermined luminosity gradation is present in a picture represented by said signal,
- (B) second means responsive to the color difference signals for providing a second indication when said at least two color difference signals remain within respective predetermined color saturation thresholds,
- (C) storage means responsive to the simultaneous presence of the first and second indications for storing values indicative of the chromaticity of said picture prevailing at that moment,
- (D) deriving means for deriving a regulating signal as a function of the stored value of the chromaticity, and
- (E) adjusting means responsive to the regulating signal for correcting defects in the color balance of the signals that determine color and luminosity of the color television picture,
- wherey defects in the color and luminosity of the picture are lessened.
A system for automatic correction of color balance signals which determine the color and luminosity of a color television signal comprising:
- (A) first means responsive to said signal for providing a first indication when a predetermined luminosity gradation is present in a picture represented by said signal,
- (B) second means responsive to said signal for providing a second indication when said picture remains below a predetermined color saturation threshold,
- (C) storage means responsive to the simultaneous presence of the first and second indications for storing values indicative of the chromaticity of said picture prevailing at the moment,
- (D) deriving means for deriving a regulating signal as a function of the stored value of the chromaticity, and
- (E) adjusting means responsive to the regulating signal for correcting defects in the color balance of serveral color difference signals that determine the color and luminosity of the color television picture,
- whereby defects in the color and luminosity of the picture are lessened and
- wherein the determination of when the color saturations in the color television picture remain below the predetermined color saturation threshold takes place as a function of the signal amplitude of normalized color difference signals.
A system for automatic correction of color balance signals which determine the color and luminosity of a color television signal comprising:
- (A) first means responsive to said signal for providing a first indication when a predetermined luminosity gradation is present in a picture represented by said signal,
- (B) second means responsive to said signal for providing a second indication when said picture remains below a predetermined color saturation threshold,
- (C) storage means responsive to the simultaneous presence of the first and second indications for storing values indicative of the chromaticity of said picture prevailing at that moment,
- (D) deriving means for deriving a regulating signal as a function of the stored value of the chromaticity, and
- (E) adjusting means responsive to the regulating signal for correcting defects in the color balance of the signals that determine color and luminosity of the color television picture,
- (F) whereby defects in the color and luminosity of the picture are lessened, wherein the signals that determine the color of the television picture are several (n in number) color-difference signals, and further comprising, for the normalization of n color-difference signals (R-Y or B-Y or G-Y, respectively),
- (G) n division circuits, each with a dividend and a divisor input and each with a quotient output,
- (H) means for feeding a color-difference signal to each of the dividend inputs,
- (I) means for feeding a luminance signal (Y) to each of the divisor inputs, and
- (J) means, at the quotient output, for tapping a color difference signal (R-Y)/(Y) or (B-Y)/(Y) or (G-Y)/(Y) normalized according to the color-difference signal.
Dependencies are inferred from the claim text.