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

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:

  • ​​Especially important to the development of the thermal imaging technologies we use today was the work of Hungarian polymath Kálmán Tihanyi (also responsible for pioneering cathode-ray TV technology)
  • In 1929, Tihanyi effectively created the first ‘night vision’ infrared video cameras for use in British anti-aircraft defences
  • During the 1970s, the technology rapidly moved towards solid-state thermal-imaging arrays, and eventually on to modern hybridised single-crystal-slice imaging devices
  • Handled units developed through the 1980s and 1990s were far more versatile, user-friendly, and didn’t require active cooling to work, unlike early mechanical versions
  • Still, thermal imaging cameras didn’t really become a financially viable option for most civil uses until the early 2000s, which saw dramatic reductions in the production costs of uncooled arrays
  • This led to a boom in the popularity of heat camera use for applications such as emergency response, architecture analysis, medical diagnostics, environmental control, and autopiloting systems.

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