How does it work?
Thermal Imaging is a competent screening tool for detecting elevated body temperature.
Here’s how it works (an overview):
- Thermal imaging cameras detect radiated infrared energy from the surface of a solid object (i.e the skin).
- The captured energy is then mathematically converted to a temperature reading.
- The temperature reading (of each pixel) on the camera then gets associated with a color, representing a temperature.
- The absolute accuracy of the camera depends on many factors. These including emissivity, detector noise/NETD, temperature drift and focus etc. (to name a few).
- Typically, a “good quality” thermal camera accuracy is +/- 2 C. This is not sufficient for elevated body temperature screening.
- The ability of a camera to obtain a correct temperature reading depends on many factors. These include subject motion, distance, environmental conditions, human body thermo-regulation etc. (to name a few).
An Important Notice!
There is a lot of misinformation currently in the public domain from companies advertising low cost equipment that is not fit for purpose.
To protect your investment, consider the following:
- Work only with reputable companies with a proven track record (in the application and science of infrared thermography). This is critical.
- Companies that sell and install equipment are not always experts in thermography. Be aware of false claims in marketing literature and websites.
- Ensure you are informed of the design and testing methodology, equipment specification, screening protocol and corresponding standards (ISO/TR 13154:2017, ISO/IEC 17025:2017, IEC 80601-2-59).
- Be aware of low cost, fully automated equipment, with false camera accuracy claims.
- The tear duct area (inner canthus, roughly 3-5mm) is the most practical (and widely adopted) measurement area. At minimum 3 pixels are required to cover this region.
- Camera’s claiming to scan large crowds are FALSE. This is not possible, the face must fill 75% of camera view. Pointing at large crowds will not provide enough resolution over the tear ducts for an exact measurement.
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