Thermal Imaging System for Human Fever Screening

A primary symptom of many infectious diseases is fever. This has lead to monitoring the temperature of pedestrians in hospitals, airports, corporate building companies, schools, and other public areas. Thermoscreen provides a non-invasive, non-contact method of screening large groups of people for elevated facial skin temperature quickly and easily. Potentially febrile individuals can be detected with minimal inconvenience and disruption to pedestrian flow.

Thermoscreen is best utilized as the first of a two-point fever detection process. At the entrance to crowded areas, Thermoscreen is used to detect individuals whose facial skin temperature is higher than normal. Fever is then confirmed using a medical thermometer. This two-point system enables large groups of people to be screened quickly and accurately to effectively prevent febrile individuals from entering areas where contagious diseases can spread easily.

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Included Components

  • [PN0800] IS640-17 Camera (60Hz, B, Lens Bayonet)

  • [PN0120] IS640 Macro Lens

  • [PN0177] Thermalyze Image Analysis Software

  • [PN0354] Thermalyze Software Module - Thermoscreen

  • [PN0359] Thermoscreen Dual Camera Enclosure

  • [PN0361] Thermoscreen Manual and Toolbag

Optional Components

  • [PN0415] System Computer for IS640-17

  • [PN0218] Thermoscreen Mat

  • [PN0219] Thermoscreen PC Stand


Optotherm's technology provides the most accurate method of mass screening for elevated facial skin temperatures that may indicate a fever. Because it is both fast and noninvasive, Thermoscreen is the best way to safeguard areas with high pedestrian flow.

Thermoscreen was originally developed in response to the need to screen large numbers of individuals for potential fever during the SARS outbreak in 2003. Thermoscreen scans subjects without contact from a distance, providing a discreet and safe method of detecting potentially feverish individuals. Over 1,000 individuals can be screened per hour so as not to restrict pedestrian flow. Thermoscreen is sold as a complete, fully tested system including a computer with preinstalled hardware and software.

Lowest Rate of Missed Detections and False Positives

Thermoscreen's sophisticated measurement process involves precision calibration, face and movement detection, ambient temperature compensation, and subject group compensation. Together, these unique features provide unparalleled ability to reduce the number of missed detections and false violations. A low false violation rate allows Thermoscreen to be employed in applications where a high number of false positives are unable to be effectively processed.

This product is currently for export only. Optotherm is currently undergoing the US FDA Premarket Notification (510k) submission process for medical devices. As soon as Thermoscreen has been cleared, this product will be available for purchase in the US.


  • Hospitals

    • Protect both patients and visitors.

  • Airports

    • Screen arriving and departing passengers.

  • Businesses

    • Safeguard the health of patrons and employees.

  • Educational Institutions

    • Help provide a safe environment for students and faculty.

How it Works

Thermoscreen's high-accuracy Infrasight infrared camera, manufactured by Optotherm, measures skin temperature by detecting and quantifying the infrared energy that is continuously being emitted from the face. As individuals walk up to the screening station, skin temperatures above a predefined threshold are detected and displayed in bright colors on the computer screen. Verbal instructions and screening results are announced through the computer's speakers and an audible alarm is activated to notify personnel that a temperature violation has occurred.

Integrated Visual Camera

A visual camera is mounted inside the camera enclosure next to the infrared camera to provide continuous visual images of subjects as they pass through the screening zone. Real-time video enables operators to quickly identify subjects as they are being screened. Highlighted areas and temperature values on the thermal image are transferred to the visual image so that operators can quickly process screening results.

Mobile Camera Stand

When mounted on the mobile computer stand, Thermoscreen can be moved quickly to alternate locations in order to screen additional groups of people or to accommodate changes in pedestrian flow. Thermoscreen is a completely passive device and emits no harmful radiation.


Communicable Diseases

Coronavirus disease 2019

COVID-19 is a contagious disease cause by the SARS-CoV-2 virus and was first identified in Wuhan, China in December 2019. It quickly spread worldwide and resulted in the COVID-19 pandemic. The symptoms of COVID-19 often include fever and transmission occurs when the virus is breathed in or comes in contact with the eyes, nose, or mouth. The COVID-19 pandemic resulted in over 700 million confirmed cases and over 7 million reported deaths globally.

Seasonal Influenza

Influenza kills over a million people worldwide every year with over 35,000 deaths in the US alone, and causes over 200,000 birth defects. It is one of the top ten causes of death in the United States. Even when yearly vaccines are accurately gauged against the prevalent strains coming from Asia, flu shots are still only 50% effective for Americans over 50. In spite of receiving flu vaccines, during an ordinary flu season in the USA, over 25% of the population is infected with Influenza.


Ebola virus disease (EVD), formerly known as Ebola hemorrhagic fever, is a severe, often fatal illness in humans that is transmitted to people from wild animals and spreads in the human population through human-to-human transmission. The average EVD case fatality rate is around 50%. The first EVD outbreaks occurred in remote villages in Central Africa, near tropical rainforests, but the most recent outbreak in west Africa has involved major urban as well as rural areas.


Middle East Respiratory Syndrome (MERS) is viral respiratory illness caused by a coronavirus called MERS-CoV primarily affecting seven countries in the Arabian Peninsula. MERS can cause severe acute respiratory illness and its symptoms include fever, cough, and shortness of breath.


The 2009 flu pandemic is a global outbreak of a new strain of an influenza A virus subtype H1N1, referred to as the "novel H1N1" first identified in April 2009, and commonly called "swine flu." It is thought to be a reassortment of four known strains of influenza A virus: one endemic in (normally infecting) humans, one endemic in birds, and two endemic in pigs (swine).

The outbreak began in Mexico and in early June, as the virus spread globally, the World Health Organization (WHO) declared the outbreak to be a pandemic. The virus spreading with "unprecedented speed" and many clinics were soon overwhelmed testing and treating patients. The virus typically spreads from coughs and sneezes or by touching contaminated surfaces and then touching the nose or mouth.

Vaccines may soon be available but may be limited and given first to healthcare workers, pregnant women, and other higher risk groups. Two or three injections will be required for maximum immunity from both the swine flu and seasonal flu. There is also concern if the new virus mutates further, it could become more virulent and less susceptible to any new vaccine.

The WHO predicts an "explosion" of swine flu cases during the remainder of 2009 and into 2010. Because the global spread of swine flu will endanger more lives as it speeds up in coming months, they are alerting governments to boost preparations for a swift response. There will soon be a period of further global spread of the virus, and most countries may see swine flu cases double every three to four days for several months until peak transmission is reached. The CDC estimates that as many as 40% of the workforce, in a worst-case scenario, might be unable to work at the peak of the pandemic due to the need for many healthy adults to stay home and care for an ill family member.

Avian Influenza

Viruses are masters of interspecies navigation.  Mutating rapidly and often swapping genetic material with other viruses, they can often jump from animals to humans. Avian and human influenza viruses can exchange genes when a person is simultaneously infected with viruses from both the common human influenza virus and the avian type. This process of gene swapping inside the human body can give rise to a completely new type of the influenza virus to which few, if any, humans would have any natural immunity. If the new virus contains sufficient human flu virus genes, transmission directly from person to person can occur.

Since the 1980s, the list of diseases that have jumped directly from animals to people has grown rapidly - hantavirus, SARS, monkeypox and, most recently, avian influenza, commonly called bird flu. Perhaps none of these illnesses has more potential to create widespread harm than bird flu. In people, bird flu usually begins much like conventional influenza, with fever, cough, sore throat and muscle aches, but bird flu can lead to life-threatening complications.

Avian flu has spread from Southeast Asia to China, Russia and now Europe. Human cases of avian influenza have been reported in Thailand and Vietnam. Researchers believe the deadly H5N1 form of bird flu has split into two distinct strains; a development that could make it harder to develop vaccines to stop the spread of the disease.


In 2003 the Severe Acute Respiratory Syndrome (SARS) virus infected over 8,200 people in 29 countries, resulting in over 700 deaths worldwide. The World Health Organization (WHO) has repeatedly warned that SARS could return and the world must be on the alert for the resurgence of the virus. During the epidemic, SARS spread rapidly by person-to-person contact in hospitals and public transportation hubs, and there was a great need to screen large groups of people for fever, a primary symptom of SARS. Conventional body temperature measurement using oral and ear thermometers, however, were too slow and inconvenient to use for mass screening. A method of fever detection was needed that was fast, accurate, and non-obtrusive and thermal imaging was the technology chosen.

Between April 23 and June 4 of 2003, 30 million travelers were screened using thermal imagers; 9,292 were assessed as having elevated temperatures and were further evaluated, 38 people were suspected as SARS virus carriers, and 21 were finally diagnosed as having SARS.


Highest Sensitivity and Specificity

The effectiveness of Thermoscreen has been studied and confirmed in the following clinical studies by the U.S. Center of Disease Control and the University of Nebraska Medical Center (UNMC) in Omaha.

Product Comparison

A number of different technologies have been evaluated and used in the past decade for mass fever screening. Below is a comparison of Thermoscreen operation and effectiveness with several of the most common mass fever screening tools.

Fixed-Mount Infrared Cameras

Thermoscreen is included in this category but is distinct from its competition by its unique method of fever screening called Automated Screening. Automated screening is a sophisticated measurement process involving precision calibration, face and movement detection, verbal commands, ambient temperature compensation, and subject group compensation. Together, these unique features provide unparalleled ability to reduce the number of missed detectons and false violations. A low false violation rate allows Thermoscreen to be employed in applications where operators cannot attend to a high number of false positives. Furthermore, automated screening significantly reduces the demands on system operators, enabling them to focus their attention on addressing fever violations.

Hand-Held Infrared Cameras

Thermoscreen has the same advantages over hand-held infrared cameras as over fixed-mount cameras. Hand-held camera however, have other important disadvantages including the following:

  • Holding the camera continuously leads to operator fatigue.

  • Camera movement (even slight movement) leads to image blur, resulting in inaccurate measurements.

  • Inconsistent screening distance between the camera and subject leads to inconsistent screening results.

  • Cameras can be easily dropped and damaged.

Infrared Spot Pyrometers

Spot pyrometers are infrared measurement devices that measure the temperature of a single area. In the case of fever screening, this area is typically the forehead. Most spot pyrometers are designed to be used in industrial applications where their accuracy is not sufficient for effective fever screening. Because temperature is measured at a single spot, cooler areas of the skin are averaged with warmer areas, making if difficult to obtain consistent temperature measurements that correlate well with internal core temperature.

Infrared Temporal Scanners

These devices require operator contact with subjects and measure temperature by swiping a hand-held probe over the temporal artery. In order to screen a different subject, a new disposable cap cover must be installed on the probe. Operation of a temporal scanner requires practice and therefore measurement accuracy is influenced by operator skill. Thermoscreen can screen over 1000 subjects per hour, more than 10 times the screening rate of temporal scanners. Additionally, all subjects can usually be screened using a single Thermoscreen system. Studies confirm the importance of using the same instrument when screening subject groups in order to obtain consistent results.


System Hardware

  • Easy to setup and operate

  • 0.05°C sensitivity; 0.3°C accuracy

  • Integrated visual camera

  • All-inclusive turnkey system

  • Mobile platform

  • No external calibration source required

Fever Screening Software

  • Simple user interface

  • Operator-free automated screening

  • Verbal commands and audible alarms

  • Automatic ambient temperature compensation

  • Verifies subject is standing still

  • Verifies subject is facing camera

  • Violation image and movie display

  • Automatic data and image logging

  • Historical data display and graphing

For general camera specifications please see Infrasight camera specifications.

Note: Thermoscreen cameras undergo a rigorous calibration process specifically designed to maximize accuracy for human fever screening measurements. Calibration temperature range and sensitivity are optimized to provide the highest sensitivity and precision when measuring the temperature of human skin. For this reason, the following temperature measurement specifications supersede the general camera specifications.

IS640-17 with Macroscopic Lens

Field of View 48 x 38°
Screening Area 181 x 136 cm
Screening Distance 2 meters
Focus Manual
Working Distance 100 mm to infinity
Focal Length 12 mm
Working F/# 1.02
Calibration Range
0 to 80°C
Sensitivity (NETD) *
Low range: < 50 mK
+/-0.3°C between 30 to 40°C; +/-1°C otherwise

* Noise Equivalent Temperature Difference (NETD) specifies the smallest temperature difference that can be detected.

Camera Enclosure and Mobile Stand Specifications

Camera Enclosure Dimensions

Camera Enclosure Weight
5 kg
Mobile Stand Weight
13 kg
Mobile Stand Dimensions
185 x 70 cm base

Fever Screening Standards

Spring Singapore
SPRING Singapore, a national standards and accreditation organization, developed and published the following technical references: Thermal imagers for human temperature screening Part1: Requirements and test methods (TR 15: Part 1: 2003 ISBN 9971-67-963-9) and Thermal imagers for human temperature screening Part 2: Implementation guidelines (TR 15: part 2: 2004 ISBN 9971-67-977-9).

These technical references were prepared by the Technical Committee on Thermal Imagers under the direction of the Medical Technology Standards Committee. Part 1 specifies the performance requirements and test methods for characterizing thermal imagers used for mass human fever screening in indoor environments. Part 2 provides users guidelines for setting up and using these systems.

Thermoscreen meets (and in many cases exceeds) all eight (8) primary and seven (7) critical performance requirements described in Part 1: Requirements and test methods.


Screening Site Example

A Thermoscreen system is placed at the entrance of a hospital to screen patients and visitors upon entering the building (see figure below). When operating in Automated Screening Mode that requires each individual to stop briefly to be screened, a single Thermoscreen station can effectively screen up to 1,200 subjects per hour.

Screening Area Setup

The screening area is climate controlled; the temperature varies from 20 to 24°C (68 to 75.2°F), and the relative humidity is approximately 70%. The screening area has diffuse ambient daylight and fluorescent lighting. The screening area is located far enough interior to minimize outside air striking the camera or screening aone that enters the building through the entrance doors.

As subjects enter the building, waist-high stanchions are setup to channel and direct them into a single file line. The screening line mat is placed 2m (6’ 6” feet) away from the camera for subjects to stand on while being screened. At this screening distance, the screening zone is 195cm (6’ 5”) horizontally. The camera is aimed and focused in order to screen subjects with height from 61 to 207cm (2’ to 6’ 9”). Any individuals taller than 6’ 9” are instructed to bend down so that their faces are in the camera’s field-of-view.

Operator Training

A hands-on training session should be conducted by the purchaser to properly train all operators. Operators are trained to operate the Thermalyze software and to adjust the camera’s aim. The Thermoscreen User Manual is kept on hand at the screening station for operator reference. The screening station logbook (not provided) is used by operators to record Thermoscreen usage and personnel on duty.

The Screening Process

Each subject is screened individually. Subjects are notified to “remove eyeglasses” (contact lenses do not need to be removed) and to “stand still and look at the camera”. Subjects can be notified verbally by the operator or by using signs positioned along the line.

The Thermoscreen System detects each subject’s face as they enter the screening zone and issues a verbal command through the computer speakers to "please stand still and look directly at the camera." After verifying that the subject is standing still and facing the camera, the screening measurement is automatically conducted and the screening result is displayed. In the case of a fever threshold violation, the audible command to "please wait here for an attendant" is issued. If screening result = Pass, "thank you, you may proceed” is issued.

Operator 1 operates the Thermoscreen system, examines the Thermal and Visual Images of subjects, and confirms Fever threshold violations. Operator 2 directs subjects into and out of the screening zone and also directs subjects whose facial skin temperature exceeds the skin threshold to the nurse station for further evaluation. If subjects are queued in line properly, screening each subject requires approximately three seconds.

Note: When screening throughput is low, a single operator can perform the tasks of both operator 1 and 2.


System Operation

Our automated screening process simplifies the screening process, reduces the demands on operators, and improves screening measurement accuracy. Thermoscreen detects when a subject’s face is in view and then issues audible instructions through the computer speakers to “please stand still and look directly at the camera” . A large TESTING button illuminates on the computer screen to indicate that an individual is currently being evaluated.

After verifying that the subject is facing the camera and standing still, Thermoscreen performs the screening measurement and then audibly issues the results. Subjects with elevated skin temperature are instructed to “please wait here for an attendant” and passing subjects are instructed “thank you, you may proceed”. You can even create custom messages for your specific screening application and language.

Highest Screening Accuracy

One of the most important benefits of automated screening is improved measurement accuracy. Because individuals are required to stand still and face the camera while being screened, more accurate and consistent measurements can be performed that more closely correlate with internal body temperature.

Automatic Compensation

Another important benefit of automated screening is automatic compensation. There are a number of factors that can affect screening measurement accuracy and effectiveness such as variations in ambient temperature and circadian cycle affects (internal body temperature generally increases during the day and decreases throughout the night). Thermoscreen compensates for these factors during operation by performing a statistical analysis of previous screening results.

Verbal Commands

Because Thermoscreen issues audible commands to instruct individuals during the screening process, operators are able to focus more attention on processing violations and line control. In fact, if screening stations are designed properly, a single operator is able to monitor multiple screening stations simultaneously.

Screening Station Design

Individuals to be screened should be channeled into a single file line. This arrangement allows the operator to more easily direct and control the flow of traffic so that potentially feverish individuals can be quickly redirected to an area where they can be further evaluated. The path of pedestrians must be designed so that subjects can be quickly and easily removed so as not to obstruct the flow into and out of the screening zone. When Thermoscreen is to be used in combination with other screening devices such as metal detectors, it is important to consider these additional screening systems during the initial planning phase and to recognize areas of potential bottlenecks. Each screening violation should be confirmed using a clinical thermometer and medical evaluation. Any cases of confirmed fever should be handled according to established medical protocols.

Fever Screening Software

Thermoscreen real-time fever screening software was designed specifically for mass fever screening. The user interface is intuitive and typical operation requires minimal operator interaction.

Visual Image Display

Live visual images of subjects can be displayed next to thermal images to allow operators to reliably identify subjects.

Fever Violation Images and Movies

To allow continued screening after a fever violation has occurred, the thermal images that were captured during the three most recent violations are displayed at the bottom of the screen. The top violation image displays the most recent violation. The time that each violation occurred is displayed above the image along with the screening measurement. Without stopping the screening process, operators are able to review and address previous violations.

To enable a more detailed review, the violation movie that was recorded during the selected violation can be replayed. Violation images, both thermal and visual, can be automatically or manually saved to hard disk for historical documentation.

Screening History

All screening measurements are recorded to hard disk to provide a historical archive that can be reviewed at a later time. Screening data can be displayed in a number of useful ways for trend analysis.