Factors to consider when specifying a thermal imaging camera for COVID-19 fever screening
31 July 2020
COVID-19 has created a worldwide demand for infrared cameras that can screen humans for a fever condition. Glenn Wedgbrow, Business Development Manager at Micro-Epsilon UK, asks: but how can you be sure the camera you choose does the job it’s supposed to do?
Many businesses are considering appropriate fever screening systems to protect their most important assets – their people. Now that staff and employees are increasingly returning to work, companies must ensure the health of returning workers is not put at risk by workers who may have become infected outside the company.
A key part of any automated fever screening system is an infrared (thermal imaging) camera. This should be easy to integrate into fever screening systems, which can then be used in real time at point-of-entry into establishments such as factories, offices and public buildings to prevent people with elevated body temperatures entering.
The basis for the effectiveness of thermal imaging cameras as a fever screening tool lies in the correlation between the outside skin surface temperature and the internal or core body temperature. There are two main approaches to fever screening: crowd-based and individual. In crowd-based fever screening, the IR camera monitors a crowd of people at once or sequentially. If the majority of the measured maximum head temperature values are coming from healthy individuals, the exceptions with an elevated body temperature can be detected.
In individual fever screenings, which are primarily used at security gates and controlled entrances, the IR camera is used to measure people one at a time. The medial canthus (tear duct) provides the strongest correlation between outside skin temperature and core body temperature and is measured more precisely from a close distance. The tear duct is located in both eyes in the corner next to the nose, where the upper and lower eyelids meet. This "hot spot" is ideally suited as a measurement point. This measuring range has a diameter of approx. 3-4mm.
Read the full article in the August issue of DPA.
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