CIRCUIT FOR PRODUCING BRIGHTNESS SIGNAL FROM OUTPUT SIGNAL OF SOLID STATE IMAGE PICK-UP APPARATUS USING SPATIAL PIXEL SHIFT

• Main Authors: SUGASAWA; MASAYUKI, YAMAMOTO; KAZUMI
• Format: Patent
• Language: English
• Published: 02.02.1993
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; PICTORIAL COMMUNICATION, e.g. TELEVISION

A color television camera including red, green and blue solid state image sensors each having a number of light receiving elements arranged in matrix for receiving said red color image to derive red, green and blue color signals, the light receiving elements of the green solid state image sensor being shifted in the horizontal scanning direction with respect to those of the red and blue solid state image sensors over a distance which is equal to a half of a pitch of the arrangement of the light receiving elements in the horizontal scanning direction, red, green and blue correlate double sampling circuits for sampling the red, green and blue color signals to derive sampled red, green and blue color signals, respectively, a delay circuit for delaying the sampled green color signal by a delay time which corresponds to a 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, red, green and blue low pass filters for removing higher frequency components of the red, green and blue color signals,red, green and blue color signal processing circuits for processing the red, green and blue color signals, respectively, a first matrix circuit for mixing the red, green and blue color signals supplied from the red, green and blue color signal processing circuits, respectively with each other at a ratio of 0.30:0.59:0.11 to derive a first brightness signal, a second matrix circuit for mixing the red color signal generated by the red correlate double sampling circuit, the delayed green color signal generated by the delay circuit and the blue color signal generated by the 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 from the second brightness signal, and an adding amplifier for adding the higher frequency component to the first brightness signal to derive a final brightness signal. The high frequency component is derived by mixing the color signals before processing the low pass filters and signal processing circuits at the ideal ratio, and thus the effect of the spatial pixel shift can be attained optimally and the resolution of the reproduced image can be increased.