Objective measurement for image defogging algorithms

Since there is lack of methodology to assess the performance of defogging algorithm and the existing assessment methods have some limitations, three new methods for assessing the defogging algorithm were proposed. One was using synthetic foggy image simulated by image degradation model to assess the defogging algorithm in full-reference way. In this method, the absolute difference was computed between the synthetic image with and without fog. The other two were computing the fog density of gray level image or constructing assessment system of color image from human visual perception to assess the defogging algorithm in no-reference way. For these methods, an assessment function was defined to evaluate algorithm performance from the function value. Using the defogging algorithm comparison, the experimental results demonstrate the effectiveness and reliability of the proposed methods.