A virtual wiper-restoration of deteriorated images by using a pan-tilt camera

In this paper, we propose a new method that can remove view-disturbing waterdrops from images by processing images taken with a pan-tilt camera system. In rainy days, it is often the case that images taken by the camera are hard to see because of adherent waterdrops on the surface of the protecting glass of the camera. In our method, an image of a distant prospect is taken at first and another image is taken after changing the direction of eyeshot. The new image is transformed with the projective transformation and compared with the first one to detect the region where waterdrops may exist. We can distinguish which image portion belongs to waterdrops by considering the distance between two waterdrop candidate regions. Finally, the region where waterdrops exist can be eliminated to merge two images. Experimental results show the effectiveness of the proposed method.