Thermal Imaging and Video Surveillance

Thermal imaging has been incorporated into video surveillance applications for many years, mostly in military and critical infrastructure environments. As the benefits of the technology became more prevalent, other vertical markets such as manufacturing and agriculture began adopting thermal imaging as well. Thermal security cameras can be configured to send alerts when changes in temperature are detected, an invaluable tool for a business that depends on machinery not overheating or refrigeration not failing. Thermal is also an advantage when the video image itself may not be clear, do to atmospheric or extremely low light conditions.

How Does Thermal Work?

Anything with a temperature above absolute zero (-273.15°C / -459.67°F) emits infrared radiation, an electromagnetic wave with wavelengths ranging from 0.7µm to 1,000µm. Although it cannot be seen by the human eye, it can be experienced, such as the infrared energy that comes from the sun. Thermal imaging cameras have special detectors that detect infrared radiation emitted by target objects or people. They calculate the corresponding relationship between the radiation energy and its temperature, and show the surface temperature of the target through different values on the display monitor.

Why use Thermal to Monitor Human Body Temperature?

Thermal is garnering attention for its ability to monitor human temperature from a distance. Human body temperature has a normal constant range from 97°F (36.1°C) to 99°F (37.2°C). Body temperature can reflect the current health of the human body, and temperature greater than this range is generally considered a fever.

Thermal imaging is an effective and efficient way to monitor temperature within large groups of people because it can be done at a distance, it is contact-free, and; has a fast detection speed. This saves manpower and material resources and allows for a seamless flow of people passing through.

Thermal temperature monitoring solutions have been deployed across the globe to mitigate the spread of the COVID-19. The solution combines a hybrid thermal network camera, a blackbody temperature calibration device, and a feature-rich, 4TB NVR.

Responsibility

Facility operators need to develop and implement appropriate policies and practices before reopening their buildings and venues, including monitoring the workforce and visitors for symptoms of COVID-19. Temperature checks are among the most prevalent recommendations, since measuring the body temperature of large groups of people can mitigate the spread of disease of which fever is a symptom.

Building upon existing video surveillance technology, a thermal imaging solution is an efficient way to get quick and accurate temperature readings. A built-in Al algorithm allows for temperature assessment of multiple people from a distance of fifteen feet away. Because no human contact is required and because many people can be screened at once, the thermal solution is well suited for crowded environments such as hospitals, airports, public transportation hubs, office buildings, and schools. It can be deployed at entrances, exits, and corridors to monitor, in real time, large groups of people as they pass through. It provides instant data to alert operators to high temperatures and determine which individuals need medical screening. In addition, it reduces manpower requirements, saves material resources, and allows for a seamless flow of people.

The Thermal Temperature Monitoring Solution requires a hybrid camera, a blackbody device, and a Network Video Recorder (NVR).

The Camera

A dual lens, fixed bullet camera that uses hybrid technology to combine thermal and visible light sensors into an integrated package. The thermal sensor provides temperature monitoring while the visible light sensor provides visual identification as a typical video surveillance camera would. The camera is able to capture an accurate temperature reading of up to thirty people per second, much faster than a handheld device, and without fear of cross-contamination. There is no need for individuals to stop in front of the camera or remove hats, glasses, or face masks; the temperature measurements can be taken as they walk past.

The Blackbody

A crucial component of the solution is the Blackbody device, which provides a constant reference temperature with which to calibrate the camera and ensure accurate temperature readings. The camera is installed facing the blackbody, which has been installed within the camera’s field of view. The camera conducts real-time comparison and correction between the temperature measured by the blackbody device and the preset temperature value in the blackbody. This continually improves the accuracy of the temperature reading; which is rated at ±0.54°F accuracy. Whereas without the blackbody thensolution may require recalibration if the ambient temperature changes, such as when a door opens and warm or cool air from outside enters, or when heating, ventilation, and air conditioning units activate. The implementation of the blackbody device means recalibration is unnecessary even with room temperature fluctuations.

The Network Video Recorder (NVR)

Both the visible video stream and the infrared video stream from the camera are inputted into a feature-rich, 4TB NVR for synchronized recording and playback. When the NVR is configured to activate the thermal alarm setting and face detection setting, it will work in tandem with the camera to send an alarm if a detected temperature exceeds a threshold established by the operator. Live events can be pushed to the mobile app, and defined temperatures can be recorded automatically. NVR based facial detection can provide positive identification of known individuals against a user inputted facial database, providing more detailed data if needed.

The Thermal Temperature Monitoring Solution is not FDA cleared nor approved. The solution should not be solely or primarily used to diagnose or exclude a diagnosis of COVID-19 or any other disease. Elevated body temperature should be confirmed with secondary evaluation methods (e.g., an NCIT or clinical grade contact thermometer). Users, through their experience with the Solution in the particular environment of use, should determine the significance of any fever or elevated temperature based on the skin telethermographic temperature measurement.