Automatic exposure control device using plural image plane detection areas

摘要

An exposure control device includes an area setting circuit which sets a light measuring area on a part of an image sensing plane; a judging circuit which detects a back light image plane on the basis of a difference in level between video signals corresponding to the inside and the outside of the light measuring area; a high luminance detecting circuit which detects a high luminance part of the image sensing plane on the basis of the video signals; and a control circuit arranged to have the light measuring area set on the image sensing plane excluding the high luminance part from the light measuring area by controlling the area setting circuit on the basis of the output of the high luminance detection circuit when the image sensing plane is judged to be a back light image plane by the judging circuit. The device is arranged to attach weight to the average levels of the signals of the inside and the outside of the light measuring area according to the result of comparison of these signals, to add the weighted average signal levels together and to perform exposure control according to the result of addition.