Abstract: As the fog image contrast reduction, we need to defog the image in order to ensure the visibility of the image. According to optics theory, the reduction of scene visibility is exponential to the scene depth. This paper proposes an image defogging algorithm based on physical model of atmospheric optics. First, the proposed algorithm estimates the ambient light in a given hazy image based on the quad-tree subdivision. Then, the proposed algorithm estimates the transmission map to maximize the contrast of the output image. Finally, image restores in the fog. The experiments demonstrate the effectiveness and practicality of the proposed algorithm.

Key words: optical principle, contrast enhancement, ambient light, image restoration