This paper describes a method for removing raindrops on a car windshield from in-vehicle camera images. Most of image-based driver assistance systems work well in good weather conditions. However, they perform poorly in rainy weather conditions because raindrops often attach to a car windshield in front of a camera. The proposed method only uses single monocular camera to remove raindrops from images. To find the regions occluded by raindrops, our method searches for similar patterns between the target frame and its previous frames in images by using DP matching. We show the performance of our method through experimental results.