The using of light field’s integral characteristic for estimation of dayligh

Light field is a physical notion that more precisely describes the light environment. Light comes to the point of view from all the sides. The situation depends on the point location in the space. For an extremely small point located in space, it is the medium spherical illumination that describes best of all the conditions of light environment. The physical meaning of spherical illumination is the integral of illumination on the infinitesimal sphere surface. It has symbol E4π that’s mean that light come to surface from all the sides.