Thermography is the front-line sensing technology to detect and isolate victims of the coronavirus (COVID-19). The non-contact thermal sensors have been ubiquitous over the past few weeks as the numbers of those contracting the virus and dying as the result of it have risen. Accuracy of the infrared (IR) thermometer gun’s measurements depends on several factors from proper operation (the right distance from the person’s forehead) to environmental factors, including recent exertion by the person being measured to temperature suppression due to taking drugs as well as their usage outside of carefully controlled health care settings.

A far more accurate technique uses infrared cameras. For example, Infrared Cameras Inc. (ICI) line of medical thermal infrared cameras have FDA 510(k) Clearance for medical use. Offering two fever detection systems priced at $5,000 and $10,000, the P-Series IR Camera is a 640 x 512 radiometric imager. The camera operates on less than 1 watt of power and uses a USB 2.0 connection to provide real time radiometric data streamed directly to a display.

Unlike the hand-held thermometer guns, the screening process involves the person being screened to stand still, look into the camera and remove any distraction such as a cap or glasses. The display includes a blackbody object for known level of infrared emissions. They provide accurate skin surface temperature readings from the first 1/1000th inch of epidermal layer.

ICI also offers a non-contact thermometer gun that costs about $25. With their gun, readings can be taken as close as 5 cm or as far as 15 cm from the target and achieve a display resolution of 0.1 °C (0.1 °F).