  Atmosphere light value is a highly critical parameter in defogging algorithms
that are based on an atmosphere scattering model. Any error in atmosphere light
value will produce a direct impact on the accuracy of scattering computation
and thus bring chromatic distortion to restored images. To address this
problem, this paper propose a method that relies on clustering statistics to
estimate atmosphere light value. It starts by selecting in the original image
some potential atmosphere light source points, which are grouped into point
clusters by means of clustering technique. From these clusters, a number of
clusters containing candidate atmosphere light source points are selected, the
points are then analyzed statistically, and the cluster containing the most
candidate points is used for estimating atmosphere light value. The mean
brightness vector of the candidate atmosphere light points in the chosen point
cluster is taken as the estimate of atmosphere light value, while their
geometric center in the image is accepted as the location of atmosphere light.
Experimental results suggest that this statistics clustering method produces
more accurate atmosphere brightness vectors and light source locations. This
accuracy translates to, from a subjective perspective, more natural defogging
effect on the one hand and to the improvement in various objective image
quality indicators on the other hand.
