<p>An image pickup system includes an IR lamp for applying infra-red ray forward, a CCD camera (5) for imaging the forward and converting it into an electric signal, and an image processing unit (7) for changing the signal accumulation time of the CCD camera (5) by a predetermined cycle and continuously and periodically outputting images of different exposure amounts. The image processing unit (7) prolongs the images of different exposure amounts in the longitudinal direction and averages signal levels of the both images after prolonged, thereby forming a combined image.</p>
