Many countries are implementing temperature screening to identify people with an elevated body temperature that may indicate fever or a coronavirus infection. Manx Technology Group has developed an inexpensive system that detects “Elevated Skin Temperature” (EST) using thermal cameras and custom software.
- The EST solution is not a medical or healthcare application, and should not be used in that manner.
- Thermal cameras are used for Fever detection systems, able to detect elevated skin temperatures.
- Advanced medical grade thermal imaging systems can be costly, with systems costing upwards of £15k.
- MTG developed a prototype EST system using off-the-shelf thermal imaging cameras and custom software.
- The MTG prototypes use best practice developed during the SARS and Ebola outbreaks, also reviewing guidance under ISO/TR 13154
- Organisations such as Amazon and Walmart screen their employee’s temperature as standard procedure.
- CDC and similar agencies are now recommending thermal screening as part of community mitigation strategies.
- We hope to make our system available for a monthly subscription, including hardware and software.
- We are looking to work with organisations who wish to trial/develop the system.
Viral and bacterial infections, such as Coronavirus spread from person to person or infected objects and surfaces.
To help contain the highly infectious virus by identifying those with high temperatures, in many advanced countries thermal cameras are being set up at airports, borders, public buildings, supermarkets and offices.
- The devices can accurately screen for elevated body temperatures quickly and reliably.
- Thermal screening must form part of a more comprehensive programme of detection, and must not be relied upon as a standalone control.
- Primary screening may identify people with elevated temperatures or fever.
- People who have signs or symptoms of Coronavirus are referred to secondary screening.
The case for fever detection systems
While there are varying views on the effectiveness of thermal screening, it is a technology that is being widely adopted by Airports, Governments and Organisations as part of a broader scheme to detect infected individuals.
Research has shown screening thermographs can detect ~30% of cases. While this is not a silver bullet, a system with a 30% detection rate is still a valuable tool as part of a more extensive system – mainly when the alternative is no screening.
The most common method for checking employee temperatures, used by Amazon.com Inc (AMZN.O), Walmart (WMT.N) and others, uses a handheld thermometer. But that limits how fast workers can enter a building and requires operators to stand inside the 6-foot (1.8 m) boundary recommended for social distancing. (Source)
EST systems (elevated skin temperatures) are specifically designed to detect elevated skin temperatures that may indicate the presence of a fever.
Simple subscription model
A subscription-based system for fever screening would improve the detection capabilities of organisations when screening staff or visitors to their premises. This could be undertaken without being intrusive and while safeguarding the health of those monitoring the systems.
- Embedded Windows 10 system with advanced thermal camera.
- WiFi and Ethernet enabled.
- Embedded 7″ screen.
- Audible alarm.
- Configurable thresholds and adaptive moving average.
- Optimal range (50cm – 1m).
- Measurement takes ~3s per person.
Not a Coronavirus diagnostic test
It is important to stress that the use of thermal cameras is not a coronavirus diagnostic test – it is purely for screening. In the event an individual is found to have an elevated temperature, there should be follow-on questions (‘How are you feeling?’, ‘Do you have a cough?’), their temperature taken using an IR thermometer and where relevant, a referral or pointed towards healthcare professionals or a helpline.
Can thermal cameras detect Coronavirus?
No. Thermal cameras can detect elevated body temperatures that may indicate a fever. With the current situation, the presence of a fever may mean the person is unwell or possibly infected with the Coronavirus. The only way to accurately identify if a person is infected is to have proper tests performed by your hospital or healthcare practitioner.
Asymptomatic people and others taking tablets such as paracetamol may not have a fever – therefore screening for temperature will not detect every case. Despite that, many people with Coronavirus will present with a fever. In any event, in your place of work or public buildings – irrespective of the cause, you may not want people attending if they have a fever!
At the end of January, a study from the London School of Hygiene and Tropical Medicine (which has not been peer-reviewed) sought to quantify the effectiveness of thermal screening. It found that, out of every 100 infected travellers taking a 12-hour flight, 42 would pass through both entry and exit screening undetected. Source
Why use Infrared thermography?
- Usual methods such as (oral, rectal, armpit, IR-ear) are intrusive and time-consuming.
- IR can be used without touching the individual and with minimal obstruction in people-flow (because it is fast and automated).
- No need for the person to touch equipment or for healthcare staff to touch the subject.
- Data can be used to form trends and provide insights into public health and key stakeholders.
What is different about your EST system?
MTG is targeting a system that is charged on a subscription basis, per site, inexpensive, yet has similar levels of accuracy – including all hardware and software. We are currently in the prototype phase but are happy to work with potential customers and partners.
Why bother with fever screening?
Fever and temperature screening is a useful tool that should be used as part of a wider-framework to test and screen individuals. A quick review of the current market suggests the most common locations for fever detection systems are:
- Airports (entry and exit screening).
- Schools, colleges and universities.
- Government buildings.
- Supermarkets and stores.
- Commercial premises.
(These are also the locations recommended by the CDC)
Where should I screen people?
ISO/TR 13154 states to support the objective of pandemic prevention, a screening thermograph with appropriate follow-up of febrile persons can be useful to separate potentially infectious individuals from others in locations such as:
- Entrances to hospitals and clinics, including emergency rooms;
- Entrances to critical infrastructure facilities;
- Entrances to workplaces;
- Entrances to schools;
- Entrances to government buildings, including police and fire stations;
- Entrances to retail and other communal locations;
- Public transportation.
Our solution is not suitable for high throughput, high footfall locations – but is ideal for a moderate amount of people going through single or parallel entrance points.
ISO/TR 13154 = Medical electrical equipment – Deployment, implementation and operational guidelines for identifying febrile humans using a screening thermography
Enforce one-in-one-out and screening
The combination of thermal imaging and people counting allow intelligence enforcement and screening of one-in-out-out policies and temperature screening.
What systems can I use?
There are a variety of specialised systems available from companies such as Flir and Hikvision. Many of these systems operate at a distance and are capable of scanning many people simultaneously. These specialised camera systems are designed for high-throughput areas and as you would expect, are not a cheap solution.
Manx Technology Group considered if the same solution could be developed at a lower price point for more moderate footfall environments, but with the same levels of accuracy.
We set about evaluating several different thermal camera models, with consideration for the hardware specification, SDK and performance. The outcome of this exercise was several prototype systems that we used for testing alongside traditional IR thermometers.
How do you measure?
Research suggests that with thermal screening, you are less interested in the absolute body temperature. Still, when measuring several people (i.e. in a queue or entrance), you should undertake a level of adaptive measurement (taking into account environmental conditions).
- Take the temperature of 20 x people. If within normal range <37.8, their measurements form the basis of a moving average.
- Anyone with a temperature that then exceeds this moving average is deemed to have an elevated body temperature potentially and should be subject to additional checks.
The use of a moving average ensures there is a level of consistency with measurement (i.e. hot day, cold day) and you are then identifying anomalies, rather than absolutes.
- The system samples the temperature at a resolution of 4,800 pixels and identifies the hotspots on a Target’s face.
- The most accessible places for accurate body temperature measurements are the Eardrum or the corner of the eye.
- Our system typically locks on to the corner of the eye as the highest temperature point.
How accurate are the cameras?
Headline figures are:
- Thermal sensitivity < 0.05°C @ +30°C (+86°F) / 50 mK
- Accuracy 4800 measurement pixels
- Minimum focus distance 15cm
- Object temperature range -10 to 150°C
- Accuracy 2% of measurement or ±2°C (±3.6°F)
- Emissivity Correction Yes – user configurable
It is essential to clarify the accuracy. These figures are across the full field of view (FOV) which may have objects in the distance or to the side and varying depths.
To enhance the accuracy, our solution proposes the subject stands 50cm away from the device, so their face is in full view. Consistent screening in this manner considerably increases the accuracy to the upper limits.
What else should I consider?
Public health authorities and businesses should consider the following controls alongside thermal screening:
- Health messages: Dissemination of health messages and travel notices informing persons on signs, symptoms, and where to seek medical support if needed.
- Primary questionnaire: Development and use of forms to collect information on symptoms, history of exposure and contact information.
- Data collection and analysis: Establishment of proper mechanisms for collection and analysis of data generated from the entry screening for the rapid evaluation and response.
How much does the EST system cost?
We are still working on the commercials, but we are targeting an inexpensive monthly subscription that includes all the components.
To find out more about the solution we are developing, please contact email@example.com, call +44 1624 777837 or click ‘Request a Quote’ on our website.
Appendix: What does the CDC, PHE, or WHO say?
The use of thermal screening attracts polarising views; however, as an elevated temperature is a recognised symptom of Coronavirus, measuring temperature seems a logical way to screen people (as opposed to diagnosing the virus itself). There were similar discussions during SARs and Ebola outbreaks. It is essential to distinguish between screening and testing.
CDC (Centre for disease control)
The CDC recommends regular health checks (temperature screening) in several different settings. Their guidance forms part of their Coronavirus Community Mitigation Strategy.
Public Health England
At the current time, PHE does not recommend temperature screening per se. However, it does feature in various guidance notes:
World Health Organisation
“Symptomatic cases may be detected through temperature screening at Point of Entry, for whom medical examination and laboratory tests will be conducted for confirmation”
Primary screening includes temperature measurement and visual observation of travellers to look for signs of illness