Abstract:Infrared optical systems provide the capability of finding a target, day and night, by sensing the temperature difference between the object and the background. Therefore, the minimum resolvable temperature difference (MRTD) can assess the performance of infrared optical systems. Herein, we present the numerical simulation of MRTD using the 3rd generation of mathematical expression of noise equivalent temperature difference (NETD). The range prediction of the system is also demonstrated based on modified Johnson criteria. MRTD of a cooled infrared optical system is measured to compare the practical situation with the theoretical simulation. The result shows a high consistency between them.