automatic focusing device

Abstract

Abstract PURPOSE:To suppress the sway of a screen when a picture changes gradually by controlling a system loop gain according to the degree of the change of a detected object. CONSTITUTION:A video signal that is inputted to a motion detection circuit 15 is A/D converted 18 and a difference signal with the video signal of previous frame that is stored at a frame memory 19 by a subtracter 20 is detected. The difference signal that is corresponded with the change of the picture between frames is compared with a setting value by a comparison circuit 16 and a control signal that controls the system loop gain so as to be decreased when the difference signal is small and increased when the signal is greater is transmitted. This control signal is given to a gain control circuit 17 and the loop gain of the system is controlled according to the changing degree of the picture.

Inventors

• 👤 Hiroyuki Harada
• 👤 浩之 原田
• 👤 Hideo Toyoda
• 👤 豊田　秀夫
• 👤 Yoshinori Kitamura
• 👤 北村　好徳

Bibliographic Details