@MASTERSTHESIS\{IMM2003-02554,
    author       = "R. S. Nielsen",
    title        = "Real Time Rendering of
 Atmospheric Scattering
 Effects for Flight
 Simulators",
    year         = "2003",
    school       = "Informatics and Mathematical Modelling, Technical University of Denmark, {DTU}",
    address      = "Richard Petersens Plads, Building 321, {DK-}2800 Kgs. Lyngby",
    type         = "",
    note         = "Supervisor: Niels J{\o}rgen Christensen",
    url          = "http://www2.compute.dtu.dk/pubdb/pubs/2554-full.html",
    abstract     = "A method to simulate the effects of atmospheric scattering in a real time rendering system is proposed. The system is intended for use in pc based combat flight simulators where the aim is to create a perceptually realistic rendering of the sky and terrain.

Atmospheric scattering is responsible for the color of the sky and for the gradual extinction and attenuation of distant objects. For flight simulators, a realistic simulation of these effects play a central role both to the emersion and to the tactical environment.

Realistic radiometric simulation of atmospheric scattering is computationally expensive in such a way that it prohibits any chance of doing it in real time. It is, however, possible to use the radiometric physics of the atmosphere as the basis of a set of simplifications that allows real time visual simulation of atmospheric scattering.

Existing methods for real time visual simulation of atmospheric scattering assumes a constant density atmosphere. This assumption will not provide realistic results in a flight simulator environment.

The proposed system expands an existing method developed by Hoffman and Preetham [10] to consider the density change in the atmosphere. In addition, parts of the model is modified to compensate for shortcomings in previous methods.

The resulting system is capable of producing visually convincing scattering effects for a range of observer altitudes and environments, and will add minimal overhead to an existing rendering system."
}