Objectives of new infrared smart sensor systems-and their focal plane processing requirements for target detection are presented. Various image processing techniques for enhancement of target-to-noise ratio by performing background clutter suppression are surveyed, including a family of statistical target estimation techniques being developed at the Naval Postgraduate School. Highlights of their results in processing a set of multiple frame infrared test images are presented using statistical spatial filters for single frames of image and statistical temporal filters and combined statistical spatial/temporal filters for multiple frames of images.