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The History of Thermal Imaging Cameras

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It’s only in the past few years that the mass production of thermal imaging technologies has reached a point where handheld thermographic cameras (also known as heat cameras, thermal detection or infrared cameras) are now an accessible option for most civil applications and/or hobbyist use.

However, viewing heat energy as an infrared spectrum display isn’t actually a new concept by any means; in fact, the roots of the basic thermography principle were established more than 200 years ago by the German-British astronomer William Herschel:

    • In simplified terms, Herschel was the first to discover the presence of infrared, all the way back in February 1800, while using a prism to study the visible light spectrum

    • Herschel found he could place a thermometer just beyond the red light end of the spectrum to detect the existence of a hitherto unknown invisible band, warmer than any of those in visible light

    • Today, we refer to this invisible band as ‘infrared’ radiation, which lies between visible light and microwave frequencies on the electromagnetic spectrum

Infrared Visable Light Spectrum

Although thermal imaging camcorders were still a long way off, Herschel’s findings were quickly used to produce a number of early thermocouple-type modules, which could detect the unseen heat emanating from warm bodies at a considerable distance. His initial discovery was further developed by many other physicists, engineers and inventors in subsequent years.

Today, the plummeting cost of cutting-edge technologies like smart sensors, microcircuitry and WiFi connectivity make thermal video cameras a popular addition to many professional and household engineering, repair, design, creative and hobbyist toolkits.

Can Infrared Cameras See Through Walls?

Well, no - but to be fair, they don’t ‘see through’ anything at all. A thermal imaging camera detects the surface temperature of the first object in its line of sight; point one at a wall or other solid surface, and it will register the heat being radiated outward by that surface.

Because most buildings are engineered and insulated to trap heat, exterior thermographic imaging seldom reveals much about what’s going on inside and vice versa. There are some caveats here: an IR camera can be used to detect extreme heat radiating from behind a wall (such as in the case of a house fire), because the wall itself would quickly heat up too.

Similarly, some thermal cameras are sensitive enough (up to +/- 0.01 Celsius) to register the warmth given off by a person, for instance, standing against the opposite side of a sufficiently thin (and cold!) wall - but only if they remain in place long enough for their own body heat to partially transfer through the materials of the wall in that spot.

Good Reasons for Routine Thermal Imaging


Due to the non-contact and non-invasive nature of thermal imaging, thermographers can carry out thermal analysis inspections while the plant or equipment is still fully operational.


Thermal imaging can detect faulty components or systems at an early stage, thus allowing the company to plan and conduct remedial work within a scheduled maintenance window. By early fault detection, damage to vital operational systems may be avoided saving thousands of dollars in unexpected down-time.


Thermal imaging surveys can quickly scan and measure the temperature distribution of entire surfaces of electrical and mechanical equipment under normal load conditions, eliminating the need for pre-inspection work and lengthy preparation.


Thermal imaging cameras (or infrared cameras), are passive instruments meaning they detect infrared energy emitted of the subjects surface. This passive and non-invasive approach ensures the thermographer can maintain a safe distance from the potentially hazardous equipment. Furthermore, there is no potential for damage to occur to the systems or equipment as a result of the thermal survey.


Intervention through early detection can prevent hazardous equipment failure, personal harm, and risk of fire. As an added bonus, and depending on your insurance policy, you may also be eligible for a discount in your insurance premiums.


Thermographic surveys support the processes involved in regulatory compliance with Health and Safety Legislation while meeting insurance specified risk assessment and prevention criteria.

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