Observer variables in minimum-resolvable temperature difference

Minimum Resolvable Temperature Difference (MRTD) has long been the universally accepted standard measure of a thermal imaging sensor's performance. This test is a complete evaluation of man and machine and is the best predictor, short of actual field evaluation, for determining the performance of the man/machine combination. Variables associated with the observer have generally been taken for granted. With the development of more sophisticated sensors for different applications, it is now time to analyze the link between the sensor and observer more closely and how it relates to the MRTD. This paper investigates the impact of the MRTD results due to observer variables such as monocular versus binocular viewing, small amount of head movement and varying viewing distance from the display. The high frequency MRTD appears to be limited by the system's MTF and amount o noise present. The low frequency MRTD appears to be affected by viewing distance and the amount of low frequency noise (non-uniformity) present.