We present a general solution of the scalar integro-differential equation of transfer of natural radiation through the atmosphere above an inhomogeneous non-Lambertian surface in the visible and near infrared ranges. The atmosphere is treated as plane-parallel, with standard vertical profiles of the volume coefficients of scattering and extinction. Within the physically acceptable limits the dependence of the reflection coefficient of the surface on horizontal coordinates and angles of incidence and reflection may remain arbitrary. A model is proposed of the field of brightness, based on this general solution. Such a model provides a methodologically high computational accuracy of algorithms of the theory of radiation transfer.