Ratio of the radiance from the target compared with that from the background in two different bands

Targets discrimination for thermal IR detection is accomplished by using threshold method . It has addressed the problem of detecting targets which are close to ambient temperature this was done by modeling the background and by using the model as a base for developing an understanding of physical processes and their variations which will lead to the construction of an algorithm to enhance target to background contrast. we have shown that by ratioing radiance received from the target and from the background, better target discrimination is possible using two bands than is the case from using one bandpass especially when target and background are of similar temperature.