An imaging system is provided, including a detection unit and a scan unit. The detection unit senses radiation of a target area. The scan unit directs the radiation to the detection unit, in which the scanning unit scans the target area N times at a constant speed within a scan period, such that each of the pixels of the target area is scanned N times by the scan unit, thereby the detection unit generates N sub-detection values for each of the pixels and adds the N sub-detection values up to generate a detection value for each of the pixels.