Automatic tracking white balance device

Abstract

Abstract PURPOSE:To obtain precise white balance without being influenced by a change of color temperature exists at the background even when the change exists during picture recording by changing over a tracking time constant of the automatic tracking type white balance following the changing-over from a non-picture recording condition to a picture recording condition. CONSTITUTION:When a trigger switch 19 of a video camera is off, namely, at the time of non-picture recording, both ends of a time constant circuit 17 are shorted and a tracking time constant of white balance is set to 0 (zero) or to a comparatively small value. Thus, to a change of color temperature information, gain control circuits 7 and 8 immediately respond, a gain of R and B is controlled and picture recording can be executed by precise white balance. On the other hand, when the trigger switch 19 is on, namely, at the time of picture recording, a switch circuit 18 is open and color temperature information signals are added to the gain control circuits 7 and 8 by the constant comparatively large tracking time constant. Thus, in this case, even when color temperature is changed in a moment within the time constant, response is slow, and the color of the object will not be influenced.

Inventors

• 👤 Hiroyuki Shimizu
• 👤 裕之 清水

Bibliographic Details