JPS5791090A - Automatic color balance adjusting device for color television camera - Google Patents

Abstract

PURPOSE:To make a color difference signal corresponding to the white detection region of a composite video signal zero, and to reproduce white correctly as white and to reproduce other colors without losing the feeling of naturality, by controlling the rate of three primary color to a constant value. CONSTITUTION:A pulse which picks up an electric signal during scanning period of white detection region is produced from a gate pulse generating circuit 36, and this pulse is applied to a color difference signal control circuit 42 and a primary color signal control circuit 30 which input a luminance signal 11Y, and red and blue primary color signals 11R and 11B and pick up the difference signal corresponding to the white color detection region and the color difference signal of the three primary color signal. The output of the circuit 30 is applied to a color difference signal generating circuit 47 via a matrix circuit 38. Outputs 46R and 46B from the circuit 42 are applied to the circuit 47, the gain of the circuit 47 is controlled, and an output signal of the circuit 47 is applied to a mixing circuit 52 together with a luminance signal 39 and it is converted into a composite video signal 15. The white balance is adjusted automatically and the change in the color recognized with eyesight against the change in the pickup state is reproduced on the reproduced picture with fidelity.