Nighttime Dehazing Based on Uneven Light Correction and Optimized Transmission
In the hazy environment at night,the images captured by the observer are characterized by low contrast and blur caused by uneven ambient illumination,a defogging algorithm based on uneven illumination correction and transmission optimization at night is proposed.Firstly,for the problem of uneven illumination,an image adaptive cor-rection algorithm based on Gamma function was used to eliminate the influence of uneven illumination on the image;secondly,since most of the night images are dark places,the atmospheric light value was obtained by improving the lo-cal atmospheric light;the rough transmission was obtained by fusing the bright channel and the dark channel through the Sigmoid function,after joint bilateral filtering refinement,the transmission at the light source was then optimized and the final transmittance was obtained using gamma function enhancement;then,the initial restoration image was obtained according to the atmospheric scattering model;finally,the guided filtering was refined to obtain the final im-age.The experimental results show that the proposed algorithm can effectively dehaze in the night scene,and can bet-ter maintain the image color contrast.
Gamma functionUneven illumination correctionLocal atmospheric lightBright and dark channel fusionNighttime dehazing
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