Transfer Requirements for Target Radiance Simulation in Optical Projection Simulators

Abstract

Valid simulation of target scenes requires spatial, dynamic, and radiance simulation fidelity. In this paper, only the target radiance (radiant sterance) and -radiance contrast simulation are analyzed, the spatial and dynamic aspects considered as being separate image transfer problems. Furthermore, only projection simulation techniques are investigated. The functional relationship between real-target radiant sterance (radiance) and required simulator source-sterance is derived from the knowledge of the radiant sterance of the real target, the transfer function and throughput factors of the optics, and the spectral responsivity of the transfer medium recording the target image. Logarithmic and linear exposure-density mechanisms are considered. It turns out that the required simulator source sterance is essentially a function of the target sterance, and the gamma and exposure in the target image recording mechanism. It is independent of target sterance for the logarithmic exposure-density mechanism if the product of the two gamma values assumed is equal to unity.