Thermal Imaging
Introduction
The COVID-19 pandemic has forced governments and companies around the world to be proactive in the development and implementation of devices that can detect symptoms of the disease. One of the symptoms of COVID-19 is elevated body temperature. The Centers for Disease Control (CDC) has stated that any temperature at or above 100.4 indicates the individual to have a fever.
Multiple technology solutions can detect a fever including; handheld forehead scanners, general electronic thermometers, and thermal camera solutions. However, one thing to consider is that none of these devices detect or identify any disease. These devices are merely tools to provide information about one of the symptoms of COVID-19 as well as any other condition or disease that increases an individual’s body temperature.
Looking at these options for detecting an elevated temperature, the handheld and electronic thermometers are only good for individual detection and their operation time is slow at best. They also do not allow for appropriate social distancing in the detection process. Thermal cameras can overcome both time and distance limitations. They can be utilized to quickly identify elevated temperatures on several individuals at one time and do so at a greater, and potentially safer, distance.
Product/Service/Methodology
To create this report, the use of white papers, as well as general internet articles were utilized in the information gathering process.
The data retrieved includes general, up to date, and easy to understand information.
Key Findings
Key Definitions of Thermal Imaging:
Radiometric thermal camera – The device is measuring the temperature of people within its field of view.
Visible Spectrum Camera – Typical video surveillance camera
Thermal Calibration Unit: “Blackbody” Device – A calibration device for the camera. It is a target object that provides a calibrated temperature. This helps the camera that is reading body temperature to calibrate to an accuracy of +/- 0.03 Celsius.
Display Device – Display for use by the monitoring individual that reveals the results coming from the thermal camera.
Video Management System/Recording System – A video recording device with storage
How Does it Work
The typical setup is to have a thermal camera facing incoming personnel. This can be regulated using a queue. A monitoring station is set up near the camera with a display that presents the camera view with detection information about each individual to a screener. Somewhere in the camera’s field of view is a blackbody device that gives the camera a calibrated known temperature.
As people enter the field of view, the camera has artificial intelligence algorithms that help it to make determinations as to whether each individual’s temperature is within a set range. It also includes software that helps it identify individual faces and then homing in on their forehead or eyes. The system then presents the positive or negative result information to the display monitor for screener review.
One item of note is that this system is designed to recognize the shape of a face, but not specific individual features. By using this detection system, it does not violate individual privacy rights (General Data Protection Regulation – GDPR in the EU).
With the inclusion of face masks, these systems will need to improve their algorithms in order to help with their recognition accuracy.
One item that needs to be taken into consideration when implementing these systems is to make sure that the environment promotes a stable temperature for the individuals being tested.
Concerns
There are two major concerns with this technology, privacy and accuracy. The Electronic Frontier Foundation (EFF) is concerned that these systems, once deployed, will not go away even after the pandemic is gone. They also question the accuracy of these systems.
Privacy is a big issue in the U.S. Individuals may question what data is being collected, whether information collected is possibly being stored and whether data is being used for other purposes. There may be concerns that these “thermal” cameras are being utilized to perform facial recognition tasks.
Experts are also warning that the accuracy of these systems could be as varied as +/- 4 degrees Fahrenheit. With this amount of discrepancy, it could lead to a lot of false positives, harassment, and unnecessary quarantining. The FDA guidelines for a “fever detection” device requires a 510K certification and a 0.9-degree margin of error.
Government Guidelines
The FDA has a guidelines white paper: Enforcement Policy for Telethermographic Systems During the Coronavirus Disease 2019 (COVID-19) Public Health Emergency: https://www.fda.gov/media/137079/download
Manufacturers of Thermal Cameras
Not a complete list, but some manufacturers are: Axis, Dahua, Flir, Hikvision, MOBOTIX, and Sunell
Visual Data
Figure 1. Components of a thermal body temperature solution
Source: “How thermal cameras can help prevent the spread of COVID-19”, Omdia
Figure 2 Strengths and Weaknesses of Thermal Solutions
Source: “How thermal cameras can help prevent the spread of COVID-19”, Omdia
Figure 3 Thermal Camera
Source: “Eagle Eye Networks Thermal Cameras for elevated Temperature Screening White Paper”, April 29, 2020
Figure 4 Visual and Thermal Images from a thermal surveillance camera
Source: “Eagle Eye Networks Thermal Cameras for elevated Temperature Screening White Paper”, April 29, 2020
