Antonio Olmedo, Marketing Manager of video product for Latin America at Johnson Controls, solves doubts about the technology of thermal cameras.
by Security Sales
As schools, hospitals and sports facilities look for ways to reopen in a world with COVID-19, thermal camera systems will play a central role in helping to detect and distinguish variations in people's skin temperature. Surveillance through thermal systems, a pillar of traditional physical security and outdoor perimeter detection, is now being used to quickly scan employees, contractors and visitors as part of a first line of defense for COVID-19 symptoms.
In these months, the security industry seeks to implement solutions with thermal cameras for customers, but there are still many doubts regarding the differences between the different types of systems and how to properly install thermal cameras. In this question session, Antonio Olmedo, Video Product Marketing Manager for Latin America at Johnson Controls, answers many of those questions.
Security Sales: What are the thermal imaging solutions on the market that detect elevated temperature in a person?
Antonio Olmedo: For the general market, there are three types of thermographic checks. There is the handheld device, which is usually lower cost, very portable and easy to use. In general, this is a point-and-shoot type device, but the user has to be about one meter (three feet) away from the person who is scanning, which, in this world we live in, means that the user must wear personal protective equipment.
We can describe the second type of solution as a set of terminal and thermal chamber. The advantage of this system over the handheld device is that it can be self-service. In this case, a person can approach and interact on their own with the terminal. However, while many of these terminal solutions have certain integration capabilities and provide some output for turnstiles or physical access controls, they do not support video management systems (VMS). A disadvantage of this type of system is that it is less accurate than a thermographic solution because it has no black-body temperature calibration device and the readings are influenced by the ambient temperature, which is usually called "thermal drift". Therefore, instead of reaching an accuracy level of ±0.3 °C, this system is likely to approach ±0.5 °C at most. Some of these devices could be considered clinical thermometers with a higher degree of accuracy at the first shot, but they offer neither the speed nor the resistance of the thermographic solution for complementary use.
And finally, there are thermal camera systems with black-body temperature calibration device. These types of systems include a camera with two sensors, one visual and one thermal, built into the camera along with a separate black-body device. Thanks to the black body and its constant calibration ability, it provides the highest level of continuous accuracy. These systems can offer much greater flexibility, as well as integration possibilities with various VMS platforms and access control devices.
VDS: What is the most important element to consider when installing a thermal camera system?
Antonio: Camera placement is critical to ensuring the system works as expected. However, the placement of the black body device that verifies that the calibration is correct is equally important. If the customer wishes to follow the recommendations of medical devices such as the FDA for camera placement, the installation of the product must respect the height instructions for the camera and the black body device, as well as the distance instructions between these devices. These instructions take into account the calibration parameters and focal range of the device to set the distance to the person to be scanned. In addition, integrators should minimise camera detection angles to ensure optimum accuracy and install – as far as possible – cameras parallel to the face, also in accordance with installation instructions.
The black body should be placed outside the area where other people might lock the device and closer to the edges of the camera's field of view. You should note that the minimum resolution required for effective thermographic readings is 320 x 240 pixels, as defined in the standards. To achieve this, you need to follow the performance standards of electrical medical equipment led by IEC 80601-2-59:2017 for human temperature scanning and FDA guidelines. To that extent, the face should occupy 240 x 180 pixels of resolution in the thermal sensor, which is roughly 50% of the sensor's visual surface, meaning that only one person is scanned at a time according to accuracy standards.
Along with height and distance considerations, the placement of the device in terms of where the system is located is crucial. For example, a large glass inlet could affect accuracy by exposure to sunlight. In the facility, it should be sought that the equipment is away from drafts and heating and cooling sources and that it is approximately five meters (16 feet) from the inlets and in an environment of as constant ambient temperature as possible between 10 °C (50 °F) and 35 °C (95 °F).
VDS: Once the thermal camera system is installed, how do I monitor the device?
Antonio: There are several options for system monitoring, depending on whether the solution is used independently or integrated with other technologies, such as intrusion detection, access control or video systems. Standalone systems receive system alerts that are typically configured through the camera's website interface, and cameras include capabilities such as the live webpage, LED alert indicators, audible alerts, and physical relay outputs. When installed correctly, these features will need to follow cybersecurity best practices, which is important for any network solution today, including changing default passwords and setting authentication methods.
These types of thermal cameras can also be integrated with turnstile systems, VMS platforms and access control system. This is achieved through the integration of a relay output, which is activated when an anomalous thermal event occurs in a thermal camera, which can be used, for example, to lock a turnstile or, through access control and video systems, send an email or an automated contagion report for contact tracing. These capabilities and integrations expand the monitoring capability above those of the standalone solution.
The camera can be configured to monitor a specific range of high and low alerts. Users can determine the actions to be taken when the alert threshold set as a minimum or maximum is exceeded. For example, a bright, visible LED that sends a visual notification through flashing lights.
VDS: What about system maintenance? Does a thermal camera require periodic service to operate accurately?
Antonio: First, it is important to make sure that the system is calibrated. This can be done once the unit is stabilized for at least 30 minutes, allowing you to set an initial reference temperature for the element known as "black body". If calibrations are performed before this heating and stabilization period, you may not achieve accurate readings. In addition, as part of the system maintenance schedule, you will need to check the calibration of the blackbody device every 12 months, in addition to following FDA and IEC recommendations. If you install the solution and do not perform maintenance work and the black body calibration certificate expires, over time, the device may exhibit temperature variations and give less accurate readings.
VDS: What advice would you give to an integrator thinking of installing a thermal camera system or to an end user planning to invest in this solution?
Antonio: Before buying a thermal camera, check that the manufacturer sends you the camera with the calibration certificate. I also recommend reading the FDA guidance published in April 2020: Enforcement Policy for Telethermal Systems During the 2019 Coronavirus Disease (COVID-19) Public Health Emergency. In this document, complementary use thermal or fever products are classified in the Class I medical device category and are subject to regulatory control. Within the framework of these regulations and categorizations, users must understand what exactly is needed to meet the necessary level of accuracy for successful detection.
While thermal camera systems are more complex than those of traditional surveillance cameras, they can be of great value once properly installed, configured and maintained.
* Antonio Olmedo is the Marketing Manager of Video Product for Latin America at Johnson Controls. He has more than 14 years of experience in the security industry and knowledge in access control, intrusion, video, fire as well as a specialization in Data Centers. He works in the company's office in Mexico City, Mexico.
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