Standoff Midwave Infrared Hyperspectral Imaging Of Ship Plumes

Combustion processes from ship engines are challenging to characterize. From a lab standpoint, important installations are typically required. Characterization of an operating ship is even more difficult as the installation of lab equipment may not always be possible. In this regard, passive remote sensing technologies present distinct advantages since they are non-invasive and do not involve installing any additional equipment on the ship itself. In addition to being relatively hot, exhaust gases from ship engines typically contain infrared-active molecules such as carbon dioxide (CO2) and carbon monoxide (CO). Therefore, infrared hyperspectral remote sensing is a technique of choice for such a system. However, characterization of operating ships is difficult due to the extent of the ship plume and the dynamics associated with the ship movements caused by the waves. Consequently, imaging techniques are preferred to single-point or scanning systems.

In this paper, characterization of an operating ferry boat was carried out using standoff midwave infrared (MWIR) hyperspectral imaging (HSI). Recording was carried out during a few minutes while passengers were transiting. Temperature maps from the ship plume as well as column density maps of exhaust gases such as CO and CO2 could be successfully determined. Combustion efficiency maps and mass flow rates were derived from these data. The results illustrate the benefits of standoff midwave infrared hyperspectral imaging as a research tool for the characterization of combustion phenomenon such as ship plumes.