Nighttime haze removal is more difficult

since nighttime hazy images contain degradation more serious than daytime's due to illumination

resulting in lower brightness

lower contrast

uneven illumination

and chromatic aberration

etc.Depending on imaging law of nighttime hazy image

a novel dehazing algorithm based on illumination estimation is presented.Firstly

the uneven illumination is removed by estimate the illumination map.Secondly

an entropy-based scheme for nighttime images is proposed to obtain transmission map.Finally

the color of illumination is estimated by statistics of source regions.The experimental results show that the proposed algorithm can effectively remove the uneven illumination effect

increase the image contrast and improve the image visual effect.