Thermal imaging screening is a procedure where a thermal camera is used to identify the surface temperature of a person or an object. These devices have become increasingly popular and widely used due to the Covid-19 pandemic.
Thermal imaging cameras are installed at airports, railway stations, offices, and other high-traffic public areas. Their purpose is to scan for people with elevated body temperatures. These devices are incredibly helpful in preventing the spread of the infection. If a person with an elevated skin temperature is detected, the operator of the thermal device is immediately notified. The person is referred to the professionals who then confirm the elevated temperature with a thermometer or any other clinical measurement device.
The device is equipped with a sensor that recognizes different levels of infrared light which is invisible to the naked eye. The captured information is translated into electric impulses which are sent to the signal processing unit. The unit translates the information into usable data for the display. Hence all the thermal devices are digital. This is a simplified explanation of how such devices work.
The camera should be installed at a height listed in the instructions, positioned so that faces of people approaching can be clearly seen on the display. It is important that the device, when placed, does not face any heat sources/heated objects as this will compromise other readings. For this reason, such devices are always installed indoors. To acquire the best reading, the temperature should not be measured immediately after a person enters the building as it takes some time for the surface temperature to adjust to the temperature of the interior. Some cameras are handheld while others are mounted on a wall or a tripod.
The area near a person’s tear duct (the area between the eye and the upper part of the nose) provides a temperature that is the closest to the human body temperature. The best thermal screening devices on the market boast an accuracy of ±0.5 °C. With some additional accessories, the accuracy can be increased to ±0.3 °C. Therefore, it is important to use a standard thermometer before any conclusions are drawn.
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