Integrated with intelligent video applications such as line crossing and intrusion detection, these cameras can automatically trigger an alert and at the same time trigger a traditional pan / tilt / zoom camera to supply pertinent video to an operator. This application becomes especially effective in perimeter protection and area surveillance applications. Thermal cameras can monitor temperatures of specified objects; if temperatures exceed or fall below a certain limit, an alarm will be triggered. They can also track highlighted temperature-spans in an image through isothermal palettes. This enables an interpretation of events in a scene. Thermal cameras are the ideal choice for the prevention of fires, equipment over-heating, damage caused by freezing, and many other hazards. Thermal sensors are only slightly affected by changing light conditions, total darkness, or other challenging weather such as rain, fog or snow. This makes thermal cameras a perfect platform on which to build more efficient, 24/7 surveillance systems.