Abstract
In this paper, we address a haze removal problem from a
single nighttime image, even in the presence of varicolored
and non-uniform illumination. The core idea lies in a novel
maximum reflectance prior. We first introduce the nighttime
hazy imaging model, which includes a local ambient illumination item in both direct attenuation term and scattering
term. Then, we propose a simple but effective image prior,
maximum reflectance prior, to estimate the varying ambient
illumination. The maximum reflectance prior is based on a
key observation: for most daytime haze-free image patches,
each color channel has very high intensity at some pixels.
For the nighttime haze image, the local maximum intensities
at each color channel are mainly contributed by the ambient
illumination. Therefore, we can directly estimate the ambient illumination and transmission map, and consequently
restore a high quality haze-free image. Experimental results
on various nighttime hazy images demonstrate the effectiveness of the proposed approach. In particular, our approach
has the advantage of computational efficiency, which is 10-
100 times faster than state-of-the-art methods