Douglas S. Goodman
Applied Optics
In practical problems of radiative transfer the methods of linear systems theory can often be used to calculate and understand better the plane-to-plane propagation of thermal radiation and scattered noncoherent radiation. In this approach the radiation on one plane due to a small surface element on the other is thought of as a spread function, its Fourier transform being a transfer function. The radiative transfer equations can then be written in either the spatial domain or the spatial frequency domain. © 1985 Optical Society of America.