Previously, we have investigated the use of Long-Wave Infra-Red (LWIR) polarimetric imaging for the detection of surface swimmers in a maritime environment. While better contrast and longer range are expected with Mid-Wave Infra-Red (MWIR) polarimetric imaging, the cost of such a system is higher than a polarimetric imager operating in the LWIR due to the advent of higher-performance micro-bolometer imaging arrays. The actual performance of a MWIR polarimetric imager to detect a person in the water is presented. A comparative analysis of system cost between MWIR and LWIR systems is also discussed.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.