Abstract : Several segmentation techniques were applied to a set of 51 FLIR (forward-Looking Infrared) images of four different types, and the results were compared to hand segmentations. There were substantial differences in performance, indicating that the choice of proper technique is very important. The segmentation techniques used were 'superslice,' 'pyramid spot detection', two versions of 'relaxation', pyramid linking', and 'superspike', One technique, 'superspike', outperformed all the others, detecting 88% of the targets and yielding only 1.6 false alarms per true target.