How is Thermal Imaging Used to Detect Pyrexia

Pyrexia – the medical terminology for an elevated body temperature – is one of the key symptoms of Covid-19. In the wake of the current pandemic, there’s been much speculation as to the accuracy of thermal imaging technology to mass screen in areas of high footfall, such as airports and other transport hubs.

We look at the technology involved, their accuracy, and their role in the fight against this and other health emergencies.

The Scope of Thermal Imaging Cameras

COVID-19 Infrared thermal imaging, scanning for health in an office
COVID-19 Infrared thermal imaging, scanning for health in an office, Image Courtesy of iStockPhoto

Thermal imaging cameras have been used for many years in airports. In recent times they have been used globally in light of the Ebola outbreak, SARS, MERS, and more. These cameras measure the body temperature in key areas – namely, the forehead and the corner of the eye. Those who’re determined as having a raised body temperature can then be subjected to further testing.

Each camera has the potential to measure the body temperature of up to 1,000 people per hour, depending on its size and specification.

What Thermal Imaging Can’t Do

Thermal imaging cannot detect viruses. This means that if a person is not displaying the symptom of a raised body temperature, then the camera is unable to flag them as a potential risk.

When it comes to mass screening, it’s necessary to ensure that the cameras have a clear view of people’s faces – in particular, the inner corner of the eye (tear duct) – to give a reading. This means the removal of eyeglasses or other facial coverings to give an accurate result.

Thermal Imaging Uses at Business Level

Thermal camera scanning used during COVID-19 pandemic in Bangkok, Thailand.
Thermal camera scanning used during COVID-19 pandemic in Bangkok, Thailand. Image Courtesy of iStockPhoto

While the current coronavirus pandemic is the obvious use for such technology right now, thermal imaging cameras have a very real role to play in many business scenarios.

Regular employee health screenings and general infection control are key areas where they can be deployed. During times of crisis, such as Covid-19 and other national and global disease spread, they can be utilized in businesses that need to remain open. This includes food stores, petrol stations, healthcare facilities, and more. Moving forward, it’s highly likely that we’ll see the continuing use of thermal imaging as routine in many places – hospitals, doctor’s surgeries, care homes, schools, etc.

The vital message that’s become far more apparent in today’s world, is the need to identify those who might be spreading an infection, and carry out appropriate investigations to prevent further contagion. The use of thermal imaging is a powerful tool with which to do this, albeit with the limitations mentioned above.

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One interesting advance is a combination of using an alerting service in conjunction with thermal imaging. Companies can take advantage of receiving immediate alerts when an individual is determined as having an elevated body temperature, allowing them to make an informed decision as to whether to take any appropriate action.

Thermal Imaging Quality is Determined by the Performance of the Hardware

While thermal imaging is by no means a new technology, the ability of a camera to deliver quality, accurate results are determined by the level of its hardware. By far the most-used and advanced models on the market are FLIR cameras. These come in a range of sizes, including mounted, handhelds, and pocket versions, manufactured by technical equipment provider companies.

Of course, the use of thermal imaging isn’t restricted to that of detecting elevated body temperatures. They’re also regularly used in non-destructing testing for electrical and mechanical equipment.

Aimal Khan is the founder & CEO of Engineering Passion. He is an engineer and has obtained his bachelor's degree in energy engineering from Kandahar University.