JPS6439186A - Setting circuit for time division white balance - Google Patents

Abstract

PURPOSE:To reduce the suppression of a saturation and to improve a color reproduction by detecting a color temperature from a color difference signal, selecting, at a switch circuit, a white balance setting value corresponding to the temperature and executing the gain control of a white balance setting by a time division. CONSTITUTION:When a color temperature is changed from a first color temperature to a second color temperature, a color difference signal 12 generates a white balance dislocation equivalent to a changing quantity and an average value 13 is correspondingly varied. In such a case, a second color temperature detecting circuit 5 detects the second color temperature, a switch 7 is closed, a switch 6 is open and the signal 12 is white-balanceset with a second white balance setting value 17. When it is thus set, the average value 13 is equalized with at the time of a white balance setting by a first color temperature white balance setting value 16 at the first color temperature, the switch 6 is closed by the first color temperature detecting circuit 4, the switch 7 is open and the signal 12 generates the white balance dislocation again. The setting values 16 and 17 are repeatedly selected in a time in accordance with the time constant of the circuit and the color temperature changing quantity by such an action and the white balance setting of the signal 12 is executed by the time division.