Thermal cameras compliment and complete your security camera network by giving you the power to see threats invisible to the naked eye, turning night into day. Thermal security cameras make images from the heat energy that is around us all the time, not from reflected visible light, giving you true 24/7 imaging capability without lights or illuminators. Thermal energy penetrates atmospheric obscurants better and farther than visible light, allowing you to see what's out there through haze, smoke, dust and even light fog. Day and night, through good weather and bad, close up and far away.
Our eyes are detectors that are designed to detect visible light (or visible radiation). There are other forms of light (or radiation) that we cannot see. The human eye can only see a very small part of the electromagnetic spectrum. At one end of the spectrum we cannot see ultraviolet light, while at the other end our eyes cannot see infrared. Infrared radiation lies between the visible and microwave portions of the electromagnetic spectrum. The primary source of infrared radiation is heat or thermal radiation.
Any object that has a temperature above absolute zero (-273.15 degrees Celsius or 0 Kelvin) emits radiation in the infrared region. Even objects that we think of as being very cold, such as ice cubes, emit infrared radiation. We experience infrared radiation every day.
The heat that we feel from sunlight, a fire or aradiator is all infrared. Although our eyes cannot see it, the nerves in our skin can feel it as heat. The warmer the object, the more infrared radiation it emits.