PURPOSE: To read image information invariably accurately without malfunction even when the illuminance of a lighting device decreases owing to a change with the elapse of time, etc., by controlling the time of a read of the image information according to illuminance detected by an illuminance detecting means and making the relation of the image information to variation in the output signal level of an image pickup means with temperature constant.
CONSTITUTION: An illuminance detector 9 controls an image signal readout time control part 11 and an illuminance control part 13 on the basis of the detected illuminance. When a decrease in the illuminance of the lighting device 1 is detected, an image signal readout time control part 11 is so controlled as to increase the image signal readout time of an image sensor 7 and the illuminance control part 13 is so controlled as to increase the illuminance of the lighting device 1 instead, so that the relation of the image information to variation in the output signal level of the image sensor 7 is made constant. The illuminance control part 13 is so controlled as to increase the illuminance of the lighting device 1 so that a desired image signal output is obtained. This control is carried out by the illuminance control part 13 according to the illuminance detected by the illuminance detector 9.
ANPO KUNIAKI
TAMURA HIROSHI
TANAKA TOSHIMASA
