Recently the standard Night Vision search and detection thermal models have been challenged with the need to address scenarios which are quite different than those for which the models were originally intended. For example, there is a need to address the characteristics of the target and background in much more detail than was previously required. This paper will discuss and illustrate a selection of new concepts and formulations being considered by the Night Vision and Electronic Sensors Directorate for incorporation in improved search and detection thermal models. Included are new proposed formulations for the mean time for detection for both field-of-view and field-of-regard search and new concepts and formulas for thermal contrast signatures of targets and clutter characterization of backgrounds. Each new concept will be individually explained in detail with mathematical formulations and imagery examples. These formulations are then combined to illustrate how they can form new model metrics which can be used to predict both the static and dynamic probability of detection. The new candidate model formulations will be matched against available measured data to show the potential improvement in predictive capability offered.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.