Color television signal processing apparatus

A color television signal processing apparatus comprising:

• a first and a second register means, including a pair of shift registers, for selectively sampling picture element levels of a first and a second color television signals at a period of one n-th (n:
• integer) of one period of a color chrominance subcarrier signal, and temporarily storing a predetermined number of successive picture element level samples,
• a switching means for selecting two chromakey operations between a first circuit operation wherein stored states of said picture element levels are refreshed with a predetermined shifting cycle and a second circuit operation wherein predetermined states of picture element levels for a color television image are circulated through one of said one pair of the shift registers with another predetermined shifting cycle,
• a calculation means for calculating correlationships, by use of signal indicative of said picture element level samples, between at least one color signal component contained in said first and second color television signals, and for issuing a predetermined correlation signal,
• a generating means for taking out at least one signal component among a chroma difference component and a luminance difference component from said correlation signal, and for generating a chromakey signal for controlling a signal level of said first color television signal, and
• a mixing means for mixing the level-controlled first color television signal with a third color television signal.

A color television signal processing apparatus responsive to first;

• and second color television signals, said color television signals having associated therewith a color chrominance subcarrier signal, said apparatus comprising:
• first register means, responsive to said first color television signal, for generating respective picture element signals indicative of said first color television signal, for generating respective picture element signals indicative of samples of said first color television signal in successive sequential time periods, said time periods being a predetermined fraction of one period of said color chrominance subcarrier signal;
• second register means, responsive to said second color television signal, for generating respective picture element signals indicative of samples of said second color television signal during said successive sequential time periods,
• calculation means, responsive to said first and second register means picture element signals, for generating a correlation signal indicative of a predetermined correlation function between said first register means picture element signals and said second register means picture element signals;
• generation means, responsive to said correlation signal, for generating a level-controlled signal indicative of said first color television signal having a signal level controlled in accordance with at least one predetermined component of said correlation signal;
• and
• mixer means for mixing said level-controlled signal with a third television signal.