Thermal detection contrast of human targets

Work on automatic detection systems based on the thermal contrast and motion of human intruders has shown that detection is sometimes difficult, depending on solar and other environmental conditions. The conditions and energy transfer mechanisms that lead to difficult thermal detection are discussed. The infrared search and track concept is described. Detection limitations due to noise and poor contrast, and detection as a function of background are discussed. The advantages of high resolution detection systems are considered. The heat flux balance equation can be used in an iterative computer program to predict the surface temperatures of both the background and the target. The main problem with this approach is that the results are only as good as the quality and the detail of the model. Since the difference between successful detection of a target and no detection is only 1 or 2 °C, small errors in the input information can easily result in incorrect conclusions. The big advantage is that doing heat flux balance calculations gives the researcher a good idea which terms are the most important for a given situation