Infrared Imaging

What makes thermography so useful?

• It is non-contact: thermography does not intrude upon or affect a target at all. We only look at naturally emitted radiation that will be there, whether we look at it or not. This is an important condition for many applications.
• It is two-dimensional: comparison between areas of the target is possible: we can measure temperature in two points or a hundred points in the same image and compare them. Thermography visualizes thermal patterns so that analysis can be done.
• It is real time

Infrared thermography defined: Infrared thermography is the science of acquisition and analysis of thermal information from a non-contact thermal imaging device.

What is Thermal Infrared Energy?

• Light and Heat: Thermal IR energy is more commonly known as "heat". Everyone is familiar with heat because of our sense of touch. But what exactly is heat? Heat is a form of light invisible to our eyes, but detectable with our skin. Visible light is part of a large spectrum of energy that includes other familiar electromagnetic energy regions: microwaves, radio waves, ultraviolet, and X-rays all are forms of light that we can not see. The colors of a rainbow form a continuous spectrum of light in the visible wavelength region as does the "light" in the other regions. Infrared light occurs at wavelengths just below red light, hence the name, infra- (below) red. Near-infrared is the "color" of the heating coil on an electric stove just before it glows red. The thermal (or mid-) infrared colors are found at even longer wavelengths.

• Glowing vs. Reflecting: Light that we see with our eyes originates from a glowing source, such as a light bulb or the sun, but that light also can reflect off of surfaces and reach our eyes. This allows us to see things that don't emit their own light. Infrared light also is emitted and reflected. Unlike visible light though, infrared light is emitted by any object that has a temperature above absolute zero. With hotter temperatures comes brighter infrared light until the object emits visible light. A good example would be a burner an electric stove.