Flesh tone correction using color difference signals

Claim 2

In a color television receiver including means for processing a received television signal and for deriving first, second and third color difference signals therefrom, said color difference signals being susceptible of fluctuation above and below a predetermined value, means for reducing aberrations in flesh tones displayed by the receiver, comprising: utilization means for receiving the color difference signals; means for transmitting the first color difference signal to said utilization means; amplifier means coupled to said means for transmitting the first color difference signals and inverting the polarity thereof with respect to said predetermined value; means for combining the amplified, inverted first color difference signal and said second and third color difference signals to form two new color difference signals each comprising predetermined portions of said amplified, inverted first color difference signal and of said second and third color difference signals; and means for applying said new color difference signals to said utilization means.

Claim 3

In a color television receiver including means for processing a received television signal for deriving luminance signals and first, second and third color difference signals therefrom, said color difference signals being susceptible of fluctuation above and below a given value, means for reducing observed aberrations in flesh tones displayed by the receiver in the presence of aberrant phase shift in the received signal comprising: utilization means for combining the luminance signals with ones of the color difference signals; first, second and third circuit means for applying the first, second and third color difference signals respectively to said utilization means; amplifier means coupled to said first circuit means for amplifying said first color difference signal by a predetermined amount and inverting the polarity thereof with respect to said given value; fourth circuit means for coupling said amplifier means to said second and said third circuit means and for coupling said second and said third circuit means together; whereby said second and said third circuit means transmit predetermined portions of said first, second and third color difference signals to said utilization means.

Claim 4

In a color television receiver including means for processing a received television signal for deriving luminance signals and first, second and third color difference signals therefrom, said color difference signals being susceptible of fluctuation above and below a given value, means for reducing observed aberrations in flesh tones displayed by the receiver in the presence of aberrant phase shift in the received signal comprising: utilization means for combining the luminance signals with ones of the color difference signals; first, second and third circuit means for applying the first, second and third color difference signals respectively to said utilization means; amplifier means coupled to said first circuit means for amplifying said first color difference signal by a predetermined amount and inverting the polarity thereof with respect to said given value; fourth circuit means for coupling said amplifier means to said second and said third circuit means and for coupling said second and said third circuit means together; whereby said second and said third circuit means transmit predetermined portions of said first, second and third color difference signals to said utilization means.

Claim 5

The invention defined in claim 2, further including switching means for selectively disabling said fourth circuit means.

Claim 6

The invention defined in claim 3, further including second switching means for selectively varying the value of the first, second and third color difference signals applied to said second and said third circuit means.

Claim 7

The invention defined in claim 4, wherein said fourth circuit means comprises a resistive network.

Claim 8

In a color television receiver including means for processing a received television signal comprising phase-modulated chrominance information, means for reducing observed aberrations in flesh tones displayed by the receiver in the presence of aberrant phase shift in the chrominance information comprising: means for deriving red, blue and green color signals from the chrominance signals, each of said color signals being susceptible of fluctuation above and below a given, median value; utilization means for receiving said color signals and producing a display therefrom, and having first, second and third input terminals for receiving ones of the color signals; first circuit means for applying said red color signal to said first input terminal; amplifier means having an input terminal coupled to said first circuit means for amplifying said red color signal by a predetermined amount and inverting the polarity thereof with respect to said given median value; second circuit means for combining predetermined portions of said blue and said green color signals with the signal outputted by said amplifier means and applying the combined signals to said second input terminal of said utilization means; and third circuit means for combining predetermined portions of said blue and green color signals with the signal outputted by said amplifier means and applying the combined signals to said third input terminal of said utilization means.

Claim 9

In a color television receiver including means for processing a received television signal comprising phase-modulated chrominance information, means for reducing observed aberrations in flesh tones displayed by the receiver in the presence of aberrant phase shift in the chrominance information comprising: means for deriving red, blue and green color signals from the chrominance signals, each of said color signals being susceptible of fluctuation above and below a given, median value; utilization means for receiving said color signals and producing a display therefrom, and having first, second and third input terminals for receiving ones of the color signals; first circuit means for applying said red color signal to said first input terminal; amplifier means having an input terminal coupled to said first circuit means for amplifying said red color signal by a predetermined amount and inverting the polarity thereof with respect to said given median value; second circuit means for combining predetermined portions of said blue and said green color signals with the signal outputted by said amplifier means and applying the combined signals to said second input terminal of said utilization means; and third circuit means for combining predetermined portions of said blue and green color signals with the signal outputted by said amplifier means and applying the combined signals to said third input terminal of said utilization means.

Claim 10

The invention defined in claim 6, wherein the signal applied to said second input terminal comprises substantially 0.3 to 0.7 of said red color signal and 0.65 to 0.45 of said blue color signal, and the signal applied to said third input terminal comprises substantially 0.05 to 0.2 of said red color signal, 0.12 of said blue color signal, and 0.0 to 0.76 of said green color signal.

Claim 11

The invention defined in claim 7, further including switching means for disabling said second and said third circuit means, whereby only said blue color signal is applied to said second input terminal, and only said green color signal is applied to said third input terminal.