A Kalman filter-based approach for adaptive restoration of in-vehicle camera foggy images

In this paper, a Kalman filter-based approach for adaptive restoration of video images acquired by an in-vehicle camera in foggy conditions is proposed. In order to realize Kalman filter-based restoration, the proposed method regards the intensities in each frame as elements of the state variable of the Kalman filter and designs the following two models for restoration of foggy images. The first one is an observation model, which represents a fog deterioration model. The second one is a non-linear state transition model, which represents the target frame in the original video image from its previous frame based on motion vectors. By utilizing the observation and state transition models, the correlation between successive frames can be effectively utilized for restoration. Further, the proposed method introduces a new estimation scheme of the parameter, which determines the deterioration characteristic in foggy conditions, into the Kalman filter algorithm. Consequently, since automatic determination of the fog deterioration model, which specifies the observation model, from only the foggy images is realized, the accurate restoration can be achieved. Experimental results show that the proposed method has better performance than that of the traditional method based on the fog deterioration model.