how to get initial estimation of transmission from hazy image ?

the atmospheric light is used for initial tranmission. but based on given equation mentioned in algorithm transmission is not found. pls give any idea to implement the

following equation.

where, B0 and B1 are boundary condition. B0=[20,20,20], B1=[260,260,260]

C indicate r,g,b.

A is atmospheric light.

paper title :Single Image Dehazing With Depth-aware Non-local Total Variation Regularization