Auto-focus controller

Abstract

Abstract PURPOSE:To discontinue the focusing action with an improper image with a device which connects the optical image of an object to be picked up to divided photosensors and controls the focusing, by providing a sequence control circuit to receive the outputs of a low sharpness deciding circuit and a correlation zone deciding circuit. CONSTITUTION:The optical image of an object to be picked up is formed on a pair of photosensors P and P'. The sensors P and P' are provided with 8 photoelectric elements. The photoelectric output of each photoelectric element is amplified by head amplifiers 1 and 1' and applied to a Fourier component extracting circuits 2 and 2'. The extracted space frequency component is applied to a phase comparator 3, and the focusing signal is delivered to a sequence control circuit device 4. At the same time, the outputs of the circuits 2 and 2' are applied to a low sharpness deciding circuit 6 and a correlation zone deciding circuit 7, and the mean photometric outputs VA and VB of the sensors P and P' are applied to a low luminance deciding circuit 8. Then the outputs of the circuits 6-8 are applied to the device 4. The focusing action is discontinued via a driving circuit 5 if the deciding signal is within a low sharpness-correlation zone. Thus the focusing action can be immediately discontinued with an improper image.

Inventors

• 👤 Akira Ogasawara
• 👤 昭 小笠原
• 👤 Sakuji Watanabe
• 👤 渡辺　朔次
• 👤 Nobuhiko Terui
• 👤 照井　信彦
• 👤 Takeshi Utagawa
• 👤 健 歌川
• 👤 Kunihisa Hoshino
• 👤 星野　邦久

Bibliographic Details