Everything You Need To Know About Thermal Imaging Cameras

A thermal imaging cameras works by detecting the infrared radiation coming from objects. This is the heat signature. To do this, the camera should be fitted with a lens to allow the infrared frequencies to pass through and focus them on a special sensor that can detect and read them.

Sensor arrays are constructed as a grid of pixels. Each of these reacts to the infrared wavelengths that hit it by converting them into electronic signals. The signals are then sent to a processor in the body of the camera which then converts them using algorithms into a colour map of different values of temperature. It is the map that is sent on to be rendered by the screen.  

Different types of thermal imaging cameras will include a standard mode of shooting that works with the visible spectrum of light, like any other point-and-click camera. This allows for effective and easy comparison of identical shots – one in infrared and one in normal mode – to help identify specific problem areas after the user steps out from behind the camera lens.

Common questions about thermal imaging cameras

Alongside the frequently asked questions about how thermal image cameras work, there are several common questions regarding the specific usage scenarios and the effectiveness of technology in particular applications and environments. In this section, we will examine a few of the best answers and the points behind them.

How do thermal imaging cameras work better at night?

These are night vision equipment that tends to work better at night. However, it has nothing to do with the state of the environment being dark or light. It is because of the ambient temperature and the core temperature of unheated objects – which is significantly lower at night time during sunlight hours. Sensors of thermal imaging cameras can display warm sectors at higher contrast. Even on cool days, heat energy from the sun is gradually absorbed by roads, buildings, construction materials, vegetation and more while it is daylight outside. For every degree, these types of objects gain an ambient temperature during the day and they become less distinguishable from other warm things that the sensor of the camera is being used to highlight and detect. For this reason, a lot of thermal imaging cameras display warm objects in sharp contrast after several hours of darkness, rather than after the sun sets.

Do thermal imaging cameras work through glass?

While you may be surprised to learn that thermal cameras do not work through glass, a full explanation of technical reasons for this is somewhat complex from the physics standpoint. The principle is straightforward. A sheet of glass allows light through but acts like a mirror for the infrared wavelengths. If you point your thermal camera at a window, what you will see on the screen would not be a clear rendering of what is on the other side. It will be a blurry mess or a reflection of yourself holding a thermal image camera.