An improved image defogging method based on dark channel prior

The method of image defogging mainly includes two aspects: image enhancement and image restoration. This article mainly focus on the image restoration. First of all, it studies the He's defogging algorithm based on dark channel prior and make some improvement based on this theory. Aiming at solving the defects of inaccurate estimation of atmospheric light and long time running of He's algorithm, the improvement of estimation of atmospheric light and transmittance are proposed in this paper. To improve the transmittance of estimation by introducing a gain coefficient instead of soft matting algorithm for long time. At the same time four binary tree subdivision method is used to estimate the atmospheric light, which is able to shorten the operation time, avoid the halo phenomenon and achieve a better defogging effect.