Thermal-imaging cameras spot flu fevers

To screen passengers for swine flu and other contagious diseases, some airports use thermal imaging cameras to see whether travelers have fevers, without having to stick thermometers in their mouths. The devices are just like regular cameras, except that instead of recording light that objects reflect, these cameras are sensitive to heat. They can even work in the dark. Recordings from these cameras show up on video screens with hotter objects looking brighter. The systems are very sensitive, measuring temperatures down to a fraction of a degree Fahrenheit, said Andrew Sarangan, an associate professor in the University of Dayton's electro-optics program.