In the urban environment, it may be necessary to identify personnel based on their type of dress. Observing a police officer or soldier might require a different response than observing an armed civilian. This paper reports on the required number of resolvable cycles to identify different personnel based upon the variations of their clothing and armament. Longwave (LWIR), and midwave infrared (MWIR) images of twelve people at twelve aspects were collected. These images were blurred and 11 human observers performed a 12-alternative forced choice visual identification experiment. The results of the human perception experiments were used to measure the required number of resolvable cycles for identifying these personnel. These results are used in modeling sensor performance tasks and improving war-game simulations oriented to the urban environment.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.