Image processing system

The invention relates to an image processing system which detects foreign matter (8, 12) on a window of a vehicle with high reliability. The system includes an image processor (1), a first lamp (2), and a second lamp (3) and when to turn on the first and second lamps (1, 2) is controlled by the image processor (1). Light from the first lamp (2) passes through the glass (4). If there are raindrops (8) on the outer surface of the glass (4), light is reflected by raindrops (8) and light from the second lamp (3) is reflected by a surface of the glass (4) and such reflected light goes through a lens (10) and an optical filter (20) with prescribed optical characteristics to an imaging device (30).