JPS6432792A - Image pickup signal processing circuit - Google Patents

Abstract

PURPOSE:To improve a color reproducibility and a luminance reproducibility to a color-temperature change by separating a color difference signal and a luminance signal into primary colors. CONSTITUTION:Color difference signals R-Y' and B-Y' and a luminance signal Y' in a color difference line successive system are separated into a primary colors signal by a signal separating circuit 50. In the circuit 50, signals R-Y are fed to an adder 11 and to the inverse input terminal of operational amplifiers 12 and 13, signals B-Y' are fed to an adder 14 and to the inverse input terminal of the operational amplifier 13, a signal Y' is fed to the non- inverse input terminal of the operational amplifier 13 and to a multiplier 15 to increase an input signal by alpha times and the output of the amplifier 12 is fed to a multiplier 16 to increase the input signal by beta times. Thus, a fourth matrix operation is executed to the input signal of the circuit 5. alpha and beta are set to optimum value in accordance with the spectral transmissivity of an additive complementary color filter and the spectral sensitivity characteristic of an image pickup element. The primary colors from the circuit 50 is executed a white balance correction and gamma correction at a next stage, and synthesized by a signal synthesizing circuit 19.