Exposure is critical in the imaging process, since if the lighting condition is poor, the quality and visibility of images will be severely degraded. In this paper, we propose a fully automatic image enhancement algorithm that can efficiently solve the under-exposed problem. The basic idea behind this method comes from the common technique of photography: the exposure compensation. For poorly exposed images like nighttime images and backlit images, we first examine the level of exposure by adapting the Zone system used in photography, and then use exposure compensation to correct the insufficient lightness. Our experiments demonstrate compared to existing methods, the proposed algorithm not only presents more nature color and visible details, but also leads to less unpleasing artifacts. It is particularly useful for image quality enhancement for a video recorded by event data recorder (EDR) or by a video-based driving assistance system in a vehicle.