These cameras typically operate in the VIS and NIR range. In addition to cameras used for security purposes, such as CCTV or traffic cameras, a wide range of cameras also operate in the IR range to detect human body temperature, such as in airports. Special filters are used to separate ambient light from the range of wavelengths which should be detected by the sensor element. Steep edges and a wide angle of incidence are crucial to the quality and performance of these filters.