A Blog by Jonathan Low


Mar 12, 2021

The Reason Some Covid Temperature Scanners Do Facial Recognition

It's a sneaky way to capture facial recognition and personal behavior data without revealing to the subject that it is doing so. The temperature scanners are not accurate and even if they were, it is increasingly evident that such scans do little to predict the presence of Covid. 

The temperature scan serves primarily as an excuse to gather the other, more valuable, information. And the danger is that it undermines public confidence in efforts to keep society safe. JL

Thomas Smith reports in OneZero:

HD temperature measurement and face recognition terminals integrate infrared temperature measurement and a “highly accurate face recognition” system that uses “deep learning algorithm[s].” It includes a network interface and can be networked into surveillance systems, which include cameras, cloud-based software and mobile apps. It can gather data about staff members or visitors, track movements, and store health data alongside face records, all without (subjects') knowledge. (And) the tablets may not even work as temperature scanners. During the pandemic, we’ve been willing to tolerate intrusion to keep our community safe. This risks eroding public trust in temperature-check procedures.

Inlate February, I went to an office building in San Ramon, California. I used to work there, before the pandemic, and needed to pick up some mail. Due to a standing Covid-19 public health order in the Bay Area, the building’s management had implemented mandatory mask and temperature checks at the entrance, so I expected to be scanned and evaluated.

I didn’t expect that the scan would be performed by a machine—or that consenting to a scan might enter me into a facial recognition database, which could later be used to monitor my health status and track my every movement.

As of late 2020, the building in question had stationed a staff member at the door with a handheld infrared thermometer and a roll of “Check Passed” stickers. After a friendly hello, she’d ensure that each visitor had a properly fitting mask and would issue a free one if they didn’t. She would then take a visitor’s temperature with a simple noncontact thermometer before handing them a sticker and sending them on their way.

On this visit, I was instead greeted by a PAR-P2TEMPTABLET temperature-scanning tablet (or Temp Tablet), made by surveillance company InVidTech. The tablet was on a pedestal near the door. A box of masks and stickers had been placed next to it. A sign instructed me to approach the tablet and perform my own temperature check.

Why would a Covid-19 temperature scanning tablet need high-grade facial recognition capabilities?

The tablet looked like an iPad with a glowing red sensor placed just above the screen. It displayed the rough outline of a human face and a live camera feed of the hallway. A message on the tablet instructed me to step up to it and center my face within the outline. When I didn’t do this properly, the tablet scolded me in a friendly but assertive female voice. On my second try, I successfully centered my face. A “temp zone” bubble appeared on my forehead. After a few seconds, my body temperature of 97.7 appeared on the screen, highlighted in green, and the voice announced, “Temperature is normal.” A nearby sign said that after my check, I could take a sticker and enter the building.

At first, the interaction seemed innocuous enough. It was a simple application of some basic automation technologies to spare a human worker the drudgery and risk of scanning potentially infectious people all day. But later I found myself wondering what would have happened if I had failed the test. If the tablet said my temperature was out of the standard range, what would prevent me from grabbing a sticker and walking into the building anyway?

Quite a lot, it turns out. The InVidTech Temp Tablet looks like a simple pseudo-medical device for taking temperature readings, but it’s actually much more than that. InVidTech bills the tablet as an “HD temperature measurement and face recognition terminal.” That’s because the tablet integrates both an infrared temperature measurement system and a “highly accurate face recognition” system that uses “deep learning algorithm[s].”

Using its embedded facial recognition tech, the Temp Tablet claims it can identify up to 20,000 unique users based on a scan of their faces with 99.7% accuracy. It turns out I didn’t even need to approach the device for it to scan and attempt to recognize my face — the Temp Tablet can recognize faces in 0.5 seconds from up to 6.5 feet away. Just by walking past it and briefly glancing at the screen, I likely gave the Temp Tablet all it needed to recognize me. The tablet also apparently includes “face liveness detection technology distinguishing real faces from non-real face spoof attacks,” as well as “real-time face mask detection” to highlight users who enter the building maskless.

Why would a Covid-19 temperature-scanning tablet need high-grade facial recognition capabilities? A demo video from InVidTech provides some potential answers. The Temp Tablet looks like a standalone device, but it includes a network interface and can almost certainly be networked into the company’s broader surveillance systems, which include a variety of networked cameras, as well as cloud-based software and mobile apps. These systems could allow the tablet to share its output — including face data — with the company’s powerful facial recognition platform. Even without networking, elements of the system’s capabilities appear to be embedded in the tablet itself, like the ability to interface with access control devices. (InVidTech did not immediately respond to a request for comment.)

The system’s capabilities are downright scary. According to the demo video, InVidTech’s facial recognition technologies “capture faces in [a client’s] video recording, and then can be used extensively for recognition purposes, databases, and much more.” The video shows the company’s Smart Face Search feature, which detects up to 32 faces at once in a video feed. An operator can then select specific faces to “enroll” them in the system’s database and add “names, IDs, and more.” Operators can also enroll faces by uploading employee ID photographs or surveillance photos.

Once a face is enrolled, the video shows how InVidTech’s software can be used to monitor and record that person’s movements around a facility, showing time-stamped clips of everywhere they’ve gone. The company’s software can also perform its face search functions retroactively. When an operator uploads a new face, they can search through historical surveillance footage to see if the depicted person has ever entered their facility before — and then they can observe all of the person’s previous movements within the facility.

One slide in the video brags that the company’s technologies are “perfect for everyday surveillance,” and another says that the systems should be used “anywhere you have people.”

One slide in the video brags that the company’s technologies are “perfect for everyday surveillance,” and another says that the systems should be used “anywhere you have people.” Specifically, InVidTech says that its technologies are ideal for “schools, banks, supermarkets, department stores, and hotels,” as well as “homes, offices, and housing communities.”

What does all this have to do with a temperature-check terminal? Let’s say I had failed my temperature check and tried to enter the office building anyway. Because the Temp Tablet is probably integrated with InVidTech’s other systems—including its ominously named Central Management Software—it almost certainly saved my face into the system’s database when I stepped up for my scan.

If I had failed my temperature check, my body temperature would have been sent to the building’s management. It’s possible that also would have been saved in the system’s database. If I tried to enter the facility, security could then track my movements from that face record (assuming the facility uses other InVidTech cameras) and either apprehend me or gather evidence about my activities to use against me later.

Even though my temperature was normal, my reading may still have been saved in the system’s database alongside my face so operators could later obtain my temperature history if I failed a future check, or for any reason at all. Another video from InVidTech suggests that I could automatically be denied entry to the building based on my temperature readings or if the system determined that I wasn’t wearing a proper mask. If I was an employee (or a student or customer) who had been entered into the system via an ID card or another method, my temperature history or any past failures to wear a mask could potentially be associated with my employment records or disciplinary records.

Even though my temperature was normal, my reading may still have been saved in the system’s database alongside my face.

In short, the Temp Tablet has powerful onboard facial recognition capabilities and is likely a complex portal into an even more powerful facial recognition and tracking system. It’s a system that can be used to gather data about staff members or visitors, track their movements, and even store health data in the form of temperature measurements alongside their face records, all without their knowledge.

This is all the more alarming because InVidTech itself admits that the tablets may not even work as temperature scanners. On the Temp Tablet product page, a disclaimer states, “InVid Tech products are not FDA approved medical devices and cannot diagnose Coronavirus infection and are not intended for use in the diagnosis of disease or other conditions or in the cure, mitigation, treatment, or prevention of disease.” The disclaimer also says, “Only a licensed medical professional can determine if a ‘hot’ individual is experiencing an abnormal medical condition.”

Plenty of medical conditions can cause an elevated body temperature in the absence of fever. An individual with one of these conditions or who happened to test higher on a given day because they had been standing in the sun or otherwise heated up their face could be denied access to their office, school, or home — or tracked and potentially disciplined — based on an incorrect or flawed reading from a device that is not even medically accurate.

The most concerning thing about the Temp Tablet, though, is that its use was mandatory to access the building, and there was no warning about its surveillance or facial recognition capabilities. This makes the tablet part of a broader trend of a Covid-enabled expansion of facial recognition and pandemic-driven intrusion of powerful surveillance technologies into people’s everyday lives.

During the Covid-19 pandemic, we’re willing to tolerate a lot of intrusion into our privacy to keep ourselves and our community members safe. Allowing a device to scan my forehead and read my body temperature already felt uncomfortably intimate and invasive. If I’d known it was also storing my reading in a massive database and using my face to track my movements, I probably would have walked right out the door instead of using it.

With InVidTech’s newest products, even this wouldn’t be enough to keep me out of a company’s database. InVidTech’s new infrared surveillance cameras are able to scan people in a crowd in less than a second each, determining their body temperature at a distance (and presumably connecting it to their face). The company even makes a camera with a “kid-friendly design that looks like a panda.” A promotional graphic shows the camera scanning children in a daycare.

In most cases, there’s no reason that a temperature scanner needs advanced facial recognition capabilities, much less a database that ties readings to users’ identities and movements. Furthermore, the use of these kinds of scanners is likely already illegal in several jurisdictions that have banned the use of facial recognition. And according to the Food and Drug Administration, thermal imaging systems “should not be used for mass temperature screening” in the first place, because they’re fallible and haven’t proven accurate for this use case.

But even where they’re legal and even if they did actually work, products like these set a dangerous precedent. They link the use of temperature checks (a positive and necessary step toward ending the pandemic) with surveillance, face databases, and tracking. That association risks eroding public trust in all temperature-check procedures. It’s already a little creepy to have someone stick an infrared wand in your face to see if you have a fever. If you have to worry that the device in use is also adding your face to a massive database, you might opt out of the procedure entirely.

The casual use of facial recognition also risks normalizing the use of what are powerful, often highly biased technologies. Linking the ability to access a person’s work, school, or home with the performance of a database-linked face scan takes a technology that should be reserved for targeted, constitutionally appropriate uses (or not used at all) and turns it into a casual element of daily life. That risks making mass surveillance an even more ubiquitous presence in our everyday reality.

Companies, schools, and housing operators should think twice before requiring visitors to consent to a face-linked temperature scan. They should also offer alternative procedures for those who choose to opt out of a face-linked scan, much like the TSA offers a manual pat-down as an alternative to millimeter wave scanners and similar tech. InVidTech does offer a privacy-first mode on the Temp Tablet, which may have been in use at my facility. (The facility’s owner did not immediately respond to a request for comment.) But even this mode still uses on-device facial recognition features. Whenever these kinds of devices are used, visitors should be informed—especially when the technologies are embedded in an invisible camera instead of a conspicuous kiosk.

Otherwise, the use of such technologies risks further eroding trust in pandemic-prevention measures — and exploiting the pandemic to entrench facial recognition even further into our everyday lives.


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