Overcoming the challenges of accurate temperature-taking
Attempts at thermal scanners by other manufacturers have achieved varying degrees of success. A number of solutions base their readings on the inexact calculation of averages, looking for outliers. These solutions need to cover larger facial surface areas and consequently might not understand the science about the number of pixels required on the target to generate an accurate radiometric output.
Another challenge affecting some devices: rapidly moving test subjects and obstacles such as face masks, hats and glasses impair their ability to function. Environmental conditions, as mentioned earlier, such as hot or cold weather, ambient temperature, a subject’s recent exercise, air conditioning or any number of variables can produce false readings by devices that can only read momentary skin temperature. Some manufacturers even claim the ability to measure temperature accurately at great distances or through the use of drones. It is possible utilizing a 6- or 7-figure military-grade camera array.
These impractical or under-performing scanners are not just a questionable investment — they can impact public health by returning false negatives, allowing actual virus carriers to pass, thereby running the risk of infecting untold others. They can also affect operations if false positives are sending people home who are not febrile.
Thermal scanner ‘goes deep’ to maximize accuracy
In contrast, WWT’s targeted thermal scanner brings improved performance by harnessing artificial intelligence (AI) and machine learning, as well as leveraging digital 3D imaging, to generate very accurate readings that are drawn from highly reliable biometric sources.
Here’s how it works: the solution is mounted on a portable cart that autonomously adjusts to the subject’s height while maintaining social distance, capturing information from up to six feet away without assistance from the attendant. It is unaffected by movement as well as eyewear, masks, hats and so forth. The solution uses an integrated thermal camera in tandem with multiple optical and depth cameras to obtain a three-dimensional facial image; it also employs software for facial feature detection to lock in on the subject’s eyes and nose, even during movement.
With this biometric information and a blackbody reference point in the Field of View (FOV), the thermal camera can target a very precise spot on the subject’s face: the arteries immediately beneath the eye sockets on either side of the nose – a site that yields a highly accurate internal temperature reading, not just a surface average. And, because the thermal beam is more focused, WWT’s solution can employ a less expensive camera than other options. This cost savings is significant: it allows customers to purchase additional cameras to cover multiple entrances rather than relying on a single testing site. As a result, the WWT thermal imaging solution can enable users to screen for temperatures of a specified maximum such as 100.4 degrees and above, flagging potential carriers for closer scrutiny.
Leveraging Intel® technology for a new approach grounded in science
Determined to produce a more scientifically accurate thermal scanner, WWT and Intel leveraged multiple leading-edge Intel® technologies. Critical to a timely rollout of their solution is the Intel® Distribution of OpenVINO™ toolkit, including its Model Zoo, which saved months of development time by establishing a starting point for refining the mathematical algorithms used for facial detection, and for analyzing and understanding the nuances of temperature variations through image processing.
Also essential to the success of this solution is the Intel® RealSense™ LiDAR Camera L515, the world’s smallest and most power-efficient hi-res LiDAR available. This unique camera dedicates 10 pixels of sensors to each side of the subject’s nose utilizing multiple optical and depth thermal lenses. In addition, we’re able to process immense volumes of captured visual data with a device powered by Intel® Core™ and Intel® Xeon® processors, which are specifically designed to provide high-performance computing (HPC) especially for intense compute workloads. These complementary Intel technologies are critical to the speed, accuracy and reliability of this new solution.
A thermal imaging solution that meets the highest standard
Conventional temperature-sensing technologies fall far short of what our world’s population needs in this critical moment as we battle a global pandemic. WWT and Intel continue to test and refine this new thermal sensor in our North American Integration Center (NAIC) to offer a new groundbreaking solution that will be in running production soon.
This thermal imaging solution is just the latest achievement in the long-running WWT and Intel partnership. Together, we are working to create a new temperature sensing solution that’s grounded in science — because the public health stakes are far too great for anything less.