As a testament to the global heightened state of awareness to threats of terrorism, local, state and national governments have been quick to respond to the recent swine flu outbreak. Airport security departments around the globe are swinging into action to protect the public and detect infected travelers. Originating in Mexico, the current swine flu, a variant of the H1N1 virus was clinically identified on April 24. Within days the new swine flu strain had spread from Mexico to the U.S., the South Pacific, Europe and the Middle East. The WHO has stopped short of recommending border closures and has not yet discouraged travel.

In an effort to stem the spread of the virus, airport security departments have turned to thermal imaging cameras for mass blind screening of passengers. These thermal cameras which have been a valuable and effective tool of industry were pressed into widespread use during the SARS scare in 2003. The sensors operate by measuring the heat emitted by all objects and converting the measurements into a digital image which reflects patterns varying heat.

Equipment is varied in configuration from the larger kiosk-style units seen at airport security stations to small hand held devices used by government and industry in the field to identify potential hazards. Recent developments allow the measurement and display of the heat signature in real-time, similar to images passing before a video camera.

Current thermal imaging implementations of the sensors are accurate, though the precision of the technology does not measure exact temperature of objects in the field of view of the thermal camera. The imaging devices are most helpful in determining the relative temperature of an object, such as an airline traveler, compared to its surroundings. When a number of passengers are viewed under the same conditions the technology can identify the individual who has a different temperature range compared to his fellow passengers. Flu victims frequently exhibit fever, high fever in some cases and these differences in temperature can be detected by the existing technology. Some models of thermal imaging cameras can even differentiate between a normal temperature, moderate fever or high fever.

Used alone these machines are not designed nor are they capable of identifying an individual as a flu victim, but taken as part of a larger system of detection and diagnosis, the technology in use by airport security departments and health agencies can aid identification of potential carriers of the swine flu virus in public places.

by Damon Wilson