Thermal cameras use infrared radiation to deliver high-res images even in low-light conditions. They can be used day or night for surveillance and airport security. Thermal cameras can measure temperatures down to a fraction of a degree. Warm objects show as white and cool objects show as black. Thermal cameras are primarily used to secure airport perimeters and help
distinguish intrusions, vandalism and theft. Thermal cameras are cost effective compared to CCTV operations because expensive lighting systems are not required to survey surrounding grounds. Thermal imaging can easily detect passengers for flu and other contagious diseases due to the passenger having a high temperature or a fever displaying brightly on the image. This screening helps to reduce the spread of infectious diseases.