Temperature Screening with HEATDEC
More than just measuring fever
Conversation with the brains behind
HEATDEC is a very accurate and intelligent measurement system for automatic fever screening and was developed for access control during the COVID19 pandemic. Stefan Clemens, authorized signatory of GTE Industrieelektronik GmbH, and Dr. Daniel Meixner, Research & Development, explain the special features
How did the development of HEATDEC come about?
Stefan Clemens: Customers asked us if we couldn’t also develop a non-contact fever measurement system, because fever is one of the symptoms of COVID-19 infections and body temperature is measured so frequently. And we have, after all, been known for decades as specialists in automation and applied sensor technology. That’s why we approached the subject of fever screening from the outset with the professionalism to which we are accustomed. This comes, among other things, from our many years of experience in early fire detection, e.g. through our industrial fire and explosion protection detection systems, ADICOS for short. We have also sought cooperation with physicians. We conduct our own test series in cooperation with hospitals.
Where did you see the particular challenges?
Daniel Meixner: A person’s body temperature is not the same on all parts of the body and is subject to diurnal fluctuations. The temperature can vary greatly even on the different parts of the face. Spot thermometers are therefore not very reliable. In-ear measurements, on the other hand, are more accurate but require face-to-face contact between visitors and staff. Automation with a thermal imaging camera was therefore an obvious choice. We opted for particularly sensitive sensors with very high accuracy in order to record and evaluate the temperature distribution over the entire face.
Stefan Clemens: Then a person’s metabolism and body temperature also vary depending on the time of day. In addition, those who work physically or are active in sports, such as cycling, may have an elevated body temperature. A sweat bath, in turn, cools down. If, on the other hand, a visitor enters a building from the cold outside, the body first readjusts the temperature. All this can lead to falsification of the measurement results and we had to take this into account.
How do you achieve these reliable measurements?
Daniel Meixner: The relationships between body temperature and other parameters are very complex. Instead of referencing a fixed threschold value of the temperature, we dynamically adapt our evaluation to the environment. The system notices whether a person steps in front of the camera in the morning or evening, from a cold or warm environment. This provides us with reliable results. If unusual values occur, for example because a face is rather hypothermic, the measurement process is extended and the evaluation is intensified according to further criteria. For this reason, no specific temperature is normally displayed after a measurement, but rather the message “OK” or “Not OK”.
Stefan Clemens: It is fascinating to see how reliably our measurement system works. HEATDEC has even proven to be predictive. It happened, for example, that a person received the indication “Not-OK” on the device display early on, although she still felt healthy at the time of the measurement. In fact, however, she became feverish a few hours later. So with HEATDEC, you can see early on when a person’s immune system is working hard.
What service can the customer expect from HEATDEC?
Stefan Clemens: HEATDEC still offers many possibilities to automate and individualize the access routine. Whether it’s a light or sound signal, a door opener, a turnstile or a freely selectable display, whether it’s on the display on site or in a remote room by security or care personnel – all of this can be set up individually. Meanwhile, the system even recognizes whether the person is wearing a mouth guard or not. By the way, there is no facial recognition with HEATDEC. It can be used in accordance with the Basic Data Protection Regulation, in Germany DSGVO. The device is robust, stable and easy to install. GTE can respond individually to the wishes of customers, continuously optimizes the measurement procedure and passes on the software updates to its customers.