Concept study for the TRM4 display-observer model: effects of glare on range performance

The aim of the range performance model TRM4 is the evaluation of imager performances considering the entire electro-optical imaging chain, including the resulting image’s observation on a display. Usually, it is assumed that the image is viewed in a mostly optimized setting, where factors such as suboptimal display contrast are not a limiting factor to the overall system. However, this cannot always be guaranteed in actual operation. For example, glare caused by light shining on the display within a cockpit in an undesirable way, or even directly into the observer’s eye, reduces the ability of pilots to perform observation tasks. Therefore, we are aiming to elaborate on non-ideal observation settings and include the influence of glare detrimental to the observer’s contrast perception in the overall range calculation. In order to model the effect of glare, we implemented a contrast threshold model based on the visual perception model of Peter G.J. Barten. We introduced a number of additional parameters further describing the display’s luminance properties to our model. Glare is modelled by a veiling luminance. The effects of glare on the imager performance are discussed based on numerical results for different scenarios. These scenarios include two imaging systems, one operating in the thermal infrared and one in the visible spectral range, with two different displays each: one regular desktop monitor and one cockpit multifunction display.