1 Aerospace Lighting Institute Technology Seminar Los Angeles, March 8-10, 2010 Presented Paper Laura Rossi laura.rossi@polito.it Politecnico di Torino, - Department of Production Systems Torino (Italy) Paola Iacomussi, Giuseppe Rossi p.iacomussi@inrim.it, g.rossi@inrim.it National Institute of Metrological Research (INRIM), - Optical Division Torino (Italy) Many factors affect display legibility in cockpits. Our research aim is to calculate perceived contrast decreasing due to veiling luminance. We focus our attention on this specific aspect, scarcely considered in aeronautical field. Through the study and development of different psychophysical models of vision and the realization of simulation experiments, parameters for the ergonomic and design of safe cockpit have been quantitatively specified. Key words: Luminance contrast, veiling luminance, glare, display legibility. 1. Summary The detection of a displayed message is the first step of the cognitive process to identify its meaning. This step can be psychophysically modelled and evaluated essentially through measurement of contrast both photometric and colorimetric. The intrinsic contrast is a physical parameter that depends on the display characteristic and on the light distribution in the environment. The perceived contrast is the real parameter of interest and it is obtained from the intrinsic contrast considering the veiling luminance evaluated with a mathematical model of the eyes properties. The threshold contrast is the minimum absolute value of the perceived contrast for seeing the object or the message: this value is influenced by the psychophysiology of the eyes and by other influence parameters like the time need to detect the target. During a flight the pilot have several tasks to do in a rapid and not sequential way. This situation and his/her distraction or fatigue can greatly modify the thresholds contrast values. Our work intends to improve the known vision models in the aeronautical field as to define or suggest pre-normative requirements. The Pilot’s eye. A physiological approach to instrument panel legibility