A Closer Look at EST Monitoring
Elevated Skin Temperature (EST) monitoring, is an extension of the field of thermography applied to measuring skin temperature. The premise of EST monitoring is to help identify one of the markers – a higher than normal skin temperature – in a person to isolate and further test them for symptoms of Sars-CoV-2 – the virus that causes COVID-19. Although a higher than normal skin temperature by no means implies that a person is infected, experts do confirm a correlation. EST monitoring allows companies to scan tens or even hundreds of people at scale to help isolate and stop the potential spread of the virus.
Infrared Thermography
Infrared Thermography (IRT, aka thermal imaging) has been widely used in commercial and industrial applications to monitor and measure air flow, water and gas leaks. Infrared cameras detect radiation in the long-infrared range (LIR) of the electromagnetic spectrum (roughly 9–14 µm) and infrared thermography makes it possible to see without any visible light (400nm-700nm).
Firefighters use thermography-based IR cameras to see through smoke, maintenance personnel use it to locate overheated joints in power lines, a sign of impending failure, and HVAC engineers use it to improve the efficiency of their heating and cooling systems. Astronomers use it to explore the depths of space.
How Does an EST Monitoring System Work?
Nearly all matter emits heat, even very cold objects like ice. Unless an object is at absolute zero (zero kelvin), its atoms are still bumping around generating heat. The human body is no exception to this. Except, you can’t see the heat given off by the human body because it’s not “hot enough” to be visible – like live coals or blazing-hot coils on an electric stove. But, infrared cameras are able to detect subtle variances in elevated skin temperature by measuring infrared radiation and subsequently, using sophisticated optics and software algorithms, creating a visual image including that of the environment.
Advantages of Contactless EST Monitoring
- No physical contact
- Faster readout than a forehead or oral thermometer
- Scientific studies show that, when used correctly, systems that measure skin temperature via infrared are generally accurate
Optical Components in IR Cameras
Infrared thermography systems vary in design from hand-held camera systems to built-in kiosks, but the typical main components are the optical lenses that are used to focus the infrared radiation, a detector, software for processing the input signals, and a display for visual readouts and images.
An important component of the IR camera is its internal optical lenses that “see” infrared wavelengths within the electromagnetic spectrum. These optics are responsible for focusing infrared energy onto the detector. The materials of these optics and the quality of the optical coating determines how efficiently infrared energy is transmitted which in turn determines the quality of the image that is generated.
Measuring Elevated Skin Temperature (EST)
- Using an IR camera that uses a baseline reference and compares the subject to the average temperature.
- Using a black body as a calibrated reference temperature source and using absolute temperature measurements.
Instead of CCDs that are used in digital cameras, the IR camera detector uses a focal plane array (FPA) of micrometer size pixels made of materials sensitive to IR wavelengths. The quality of the lenses (pixel density) and the software algorithms drives the resolution and hence accuracy of the temperature readout, but one can achieve precision within ±1°C.
The lenses in the optical assembly of the IR cameras demand a high-performance anti-reflective (AR) coating for best results. EMF, offers HEAR (High Efficiency Anti Reflective) and DLC (Diamond-Like Carbon) coatings on most IR substrates including Germanium (Ge), Silicon (Si), Zinc Selenide (ZnSe), Zinc Sulfide (Zns) and Chalcogenides.
