Journal of Xidian University

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Superpixels-based golden dark channel for single image fog removal

WANG Yunfei;LIU Huawei;ZHAO Boxin   

  1. (College of Aeronautics and Astronautics Engineering, Air Force Engineering Univ., Xi'an 710038, China)
  • Received:2016-09-25 Online:2017-10-20 Published:2017-11-29

Abstract:

Fog and haze can cause serious image degradation. In the light of the limitations of dark channel theory, the fog concentration is supposed to be constant locally, and the effectiveness of dark channel prior decays exponentially as the depth increases. Based on this, we propose a superpixels-based golden dark channel algorithm for single image fog removal. Small regions are obtained by superpixels in which the fog concentration and the depth remain constant. The golden dark channel is computed in these regions. The resulting transmittance remains constant and is finer and more precise. This method can suppress the “Halo effect” which occurs in depth mutation. Moreover, An iterative strategy is employed to gradually reduce the overall density of fog, making the residual amount of fog satisfy the golden section after each iteration. Further, the golden section is used to simplify the tolerance value and deal with the color cast problems in the sky region where the depth is infinity. Experimental results show that the algorithm can effectively improve the image of visibility, and performs even better when the fog concentration is greater.

Key words: image defogging, atmospheric scattering model, superpixels, golden dark channel, transmittance