Video signal correction system with low chrominance circuit for modifying currections

A low chrominance level color corrector for providing selectively variable color correction at low chrominance levels, comprising:

• correction signal means for providing a plurality of video signal correction signals for correcting a parameter of said uncorrected input video signal;
• operator means for modifying said plurality of video signal correction signals:
• of correction signals;
• correction means responsive to said selected particular one of said pluarlity of correction signals for correcting said uncorrected input video signal to provide a corrected video output signal;
• means responsive to said uncorrected input video signal for providing a low chroma signal which vaires with the magnitude of the chrominance envelope of said uncorrected input video siganl;
• upper limiting means for providing an upper voltage limit for the excursion of said low chroma signal, said upper voltage limit corresponding to the provision of full correction for said uncorrected input video signal;
• lower limiting means for providing a lower limit for the excursion of said low chroma signal, said lower limit corresponding to the provision of minimal correctionfor said uncorrected input video signal;
• and
• means responsive to said low chroma signal for varying the magnitude of said selected particular one of said plurality of correction signals in correspondence with the magnitude of said low chroma signal.

A low chrominance level color corrector for providing selectively variable color correcton at low chrominance levels, comprising:

• filter means for providing a chroma signal from an uncorrected input composite video signal;
• a video detector circuit for providing an output voltage which varies with the magnitude of said chroma signal;
• a positive clipping circuit for setting an upper limit for said output voltage of said video detector circuit;
• a negative clipping circuit for setting a lower limit for said output voltage of said video detector citcuit;
• a clamping circuit for clamping said output voltage of said video detector circuit under predetermined circumstances;
• an amplifier for amplifying said output voltage of said video detector circuit;
• and
• correction means responsive to said amplified output voltage for providing correction for a video parameter as a function of the magntiude of said amplified output voltage.