1. General position of the problem

The detection performance of an optronic system is defined by the objectives and mission assigned to the system (for example, the error rate per bit for a telecommunications optronic system). In the case of a system tasked with the surveillance and defense of an area, performance is generally expressed in terms of its detection range, i.e. the distance beyond which surveillance can no longer be carried out with the required quality. For an infrared imaging system, performance is expressed in terms of the minimum temperature difference it can detect, and so on.

In each case, the designer must carefully analyze the spatial, spectral and temporal characteristics of the signal to be detected in order to best adapt the optronic system, but this approach is not sufficient to deduce the system's performance. Other parameters, external to the system, may come into play,...