Can Thermal Cameras Be Used to Detect COVID-19?
Thermal cameras have been used to detect elevated body temperatures by airports for many years.
Can thermal cameras be used to detect the presence of the COVID-19 virus? There’s currently considerable debate in the market around whether these claims are correct. What other options could an organisation deploy when seeking to ‘keep an eye’ on staff health during the COVID crisis?
A: Thermal body temperature cameras can’t detect a virus, but they can detect elevated body temperatures in public and private spaces in a rapid, non-invasive way, alerting security and healthcare teams to the need to test scanned subjects for illness in a way that does not slow the flow of foot traffic.
Because these cameras are measuring skin temperature, not core temperature, expect false positives and integrate this expectation into procedures. Be aware that few, if any, manufacturers have undertaken empirical studies in tandem with health authorities to check the capabilities of BTM cameras when used to detect underlying health conditions. What this means is that no absolute claims can be made about performance. BTM cameras are a useful tool but they are not the whole answer.
There are challenges. Operationally, it’s important that BTM cameras can see the forehead or corner of the eye – that means no hats or glasses can be worn – and BTM cameras should be placed no more than 2 metres away from subjects. Security teams must also be sure the environment has no strong light sources, sunlight or people not being tested in it. Further, people who are asymptomatic – that might include a large number where COVID-19 is concerned – may not show an elevated temperature.
Be sure the display mechanism is sufficiently subtle to show slight temperature differences. Controlling the environment is vital – you need temperatures between 18-24 degrees and make sure the equipment you select has a noise equivalent temperature difference of 50mK – that’s 0.05C – and a spectral range between 7.5 and 13 microns. You also want low latency in the image stream and higher resolutions. The standard relating to the use of thermographic cameras is ISO 13154 – make sure you’re across it before you apply this technology to your site.
Be aware BTM camera ‘thermometers’, which have generally been designed and manufactured to check temperatures of plant equipment or to image intrusion of warm bodies in high contrast external environments, are not a magic bullet for virus detection. When it comes to COVID-19 detection, only a proper medical test can establish infection. What this means is that BTM camera stations must be supported by proper medical procedures that can be immediately enacted to assist subjects after elevated temperatures have been detected.
An alternative to BTM cameras when it comes to detecting elevated temperatures in staff, would be to implement trust-based procedures that required them to take their own temperatures at home before coming to work, and to immediately visit a COVID test station, then self isolate, if their temperature exceeded a particular threshold.