Fusion of dark channel filtering and spatial pyramid image defogging algorithm

For the problem of poor infrared image quality in foggy weather, this paper proposes a dark channel filtering and spatial pyramid algorithm(DCF-SP) for defogging maritime infrared image.Firstly, the sea-sky region is segregated by the adaptive algorithm in the image.And then,the sky region of image is divided into four subspaces to locate the subspace with the largest average gray value.The maximum brightness of neighborhood pixels in the brightest sub-block is regarded as the atmospheric light estimate after three iterations.The minimum filtering of clear and foggy infrared images is carried out to obtain the prior knowledge that the dark channel value of clear infrared images tends to zero,finally,estimate the dark channel transmittance, and realize the haze removal of infrared images.Compared with the existing defogging algorithm, experimental results show that, the DCF-SP algorithm has higher robustness and shorter running time, and can retain the edge information of image targets more effectively. EPI and SSIM metric achieve 0.95 and 0.9425 respectively.