Circuit for producing brightness signal from output signal of solid state image pick-up apparatus using spatial pixel shift

A color television camera comprising:

• an objective lens for forming an image of an object to be picked-up;
• a color separating optical system for separating said image of the object into red, green and blue color images;
• a red solid state image sensor having a number of light receiving elements arranged in matrix for receiving said red color image to derive a red color signal;
• a blue solid state image sensor having a number of light receiving elements arranged in matrix for receiving said blue color image to derive a blue color signal;
• a green solid state image sensor having a number of light receiving elements arranged in matrix for receiving said green color image to derive a green color signal, said light receiving elements being shifted in the horizontal scanning direction with respect to those of said red and blue solid state image sensors over a distance which is equal to one-half of a pitch of the arrangement of the light receiving elements in the horizontal scanning direction;
• a red correlate double sampling circuit for sampling said red color signal to derive a sampled red color signal;
• a green correlate double sampling circuit for sampling said green color signal to derive a sampled green color signal;
• a blue correlate double sampling circuit for sampling said blue color signal to derive a sampled blue color signal;
• a first delay circuit for delaying the sampled green color signal generated by said green correlate double sampling circuit by a delay time which corresponds to one-half of a pitch of the arrangement of the light receiving elements viewed in the horizontal scanning direction to derive a delayed green color signal;
• a red low pass filter for removing a higher frequency component of said sampled red color signal generated by said red correlate double sampling circuit to derive a filtered red color signal;
• a blue low pass filter for removing a higher frequency component of said sampled blue color signal generated by said blue correlate double sampling circuit to derive a filtered blue color signal;
• a green low pass filter for removing a higher frequency component of said delayed green color signal generated by said first delay circuit to derive a filtered green color signal;
• a red color signal processing circuit for processing said filtered red color signal to derive a processed red color signal;
• a green color signal processing circuit for processing said filtered green color signal to derive a processed green color signal;
• a blue color signal processing circuit for processing said filtered blue color signal to derive a processed blue color signal;
• a first matrix circuit for mixing said filtered red, green and blue color signals supplied from said red, green and blue color signal processing circuits, respectively with each other at a first ratio to derive a first brightness signal;
• a second matrix circuit for mixing said red sampled color signal generated by said red correlate double sampling circuit, the delayed green color signal generated by said first delay circuit, and said blue sampled color signal generated by said blue correlate double sampling circuit at a ratio of 0.25:0.5:0.25 to derive a second brightness signal;
• a band pass filter for extracting a higher frequency component of said second brightness signal;
• and
• an adding amplifier for adding said higher frequency component to said first brightness signal to derive a final brightness signal.