Beware Rigged China Fever Cameras

By: Ethan Ace and John Honovich, Published on Sep 08, 2020

Many China fever camera manufacturers have rigged algorithms dynamically adjusting temperatures to more 'normal' results, IPVM has concluded from 6 months of testing 20+ devices. See the 80-second video below overviewing this:

This raises the risk of missing actual fevers and creates a false sense of safety while producing more 'normal results', since nearly everyone has 'normal' temperatures, even if subjects being measured have characteristics (e.g., eyeglasses, hats, hair bangs, walk in groups or at sharp angles to the device, etc.) that fundamentally undermine thermal temperature screening.

Deceptive Marketing

Fever camera manufacturers claim to detect fevers in all sorts of amazing conditions:

IPVM Image

This has created false expectations among the public.

Actual / Accurate Thermal Imaging

To the contrary, science, global IEC standards, and US FDA guidelines all have determined the proper and correct way to conduct fever screening with thermal systems is to directly measure and report the temperature captured, as-is:

IPVM Image

These images (from the IEC and FDA respectively) are, of course, in sharp contrast to the explosion of deceptive manufacturer marketing.

Get Notified of Video Surveillance Breaking News
Get Notified of Video Surveillance Breaking News

What Fevers Actually Look Like On Thermal

Accurate temperature screening with thermal systems depends on measuring a tiny section of the face that can be obscured by glasses, hats, hair bangs, etc. In the graphic below, shown in red, we contrast the false expectations that people often have (left) with the small area (on the right) where accurate temperatures can potentially be measured.

IPVM Image

Anywhere outside of that tiny area of the face, the temperature is moderate to significantly cooler so readings that miss that tiny area hide actual fevers and produce too low results.

The fascinating element we found in our testing is that these China systems do not produce extremely low results (like 92°F or 94°F or 95°F) even with conditions that fundamentally block actual thermography from getting a good reading.

Skateboard Example

So how do these China systems get near 'normal' temperatures of a person even when zooming by on a skateboard?

Rigged Results

Many China systems we tested rig measurements using "compensation" algorithms to estimate skin temperature. So for example, when the measured max temperature of a person is ~91°F, the camera might add 6 degrees reporting them at 97°, but when measured at 94°, it might add just 4 degrees, reporting them at 98°.

The chart below shows our findings from one of our tests:

IPVM Image

This is clever but dangerous. It is clever since these algorithms correctly assume most people have normal temperatures, so they disproportionately increase low readings into more normal ones. And since almost no one has a fever at any given time, it is typically right even if the process is wrong / rigged.

It is dangerous because when the system has an obvious bad reading (like a guy zooming by on a skateboard) it gives a false sense of accuracy. The guy on the skateboard probably does not have a fever since very few have fevers but a thermal system can not determine that directly, since the angle of incident and the speed of the skateboarder makes that impossible.

Missed High Temperatures

The key risk of these algorithms is missed fever temperatures. Because the system corrects readings to more "normal" human temperatures, a subject with a 100°F temperature might be measured as only 98°F.

IPVM Image

While these systems will be "accurate" when reporting on people with normal body temperatures (~98°F) and may trigger on those with high fevers, missing low grade elevated temperatures is a systematic problem we found in our testing.

Unrealistic Readings

Second, fever cameras display nearly “normal” temperatures on practically any face they detect, so even covering the top half of a person's face (with a piece of cardboard), the camera still provides a measurement close to body temperature:

While the fever camera thought the cardboard was a human forehead, it reported it at 95.2°F, the actual temperature of the cardboard was just 86.4°F.

Indeed, a paper printout of a face is measured at normal body temperature, despite only reading 91° on a calibrated thermometer.

Against Accepted Thermography

This goes against global standards and accepted thermography, as the Chairman of the Board of the American Academy of Thermology declared:

Compensating or self-correcting any temperature would be totally unacceptable. On what basis are they doing that? What do they think they're even measuring temperature if they're just changing the temperature [displayed]?

Multiple People Measured The Same

Finally, these systems produce extremely similar temperature measurements when multiple subjects are measured. For example, in this clip, all three subjects are measured at 99°, even though their temperatures varied .5-by over 1°F according to a calibrated thermometer (97.9-99°F).

Risk: Missed Fevers, Endangering Others

In our testing of 20+ 'fever' devices, we found most China systems show one or more of these issues, failing to accurately detect moderately elevated temperatures. In particular, see our in-depth tests of:

These rigged algorithms' favoring 'normal' / statistically average temperatures produce a false sense of safety and raise the risk of infectious people passing inside one's facility.

3 reports cite this report:

Axis Compares Fever Camera Sellers to 9/11 on Sep 18, 2020
Axis Communications, the West's largest surveillance camera manufacturer, has...
Avigilon Elevated Temperature Detection Camera Tested on Sep 17, 2020
Avigilon has entered the temperature screening market with the release of...
Dangerous Hikvision Fever Screening Marketing In Africa on Sep 15, 2020
A multi-national African Hikvision distributor is marketing dangerously...

Comments (7)

Only IPVM Members may comment. Login or Join.

Love the cardboard and the paper print out reading at a normal temp! Clips like that really help get the point across to people who aren't questioning the validity of these devices.

A simple demonstration to help a layperson spot a scam.

Quite frankly the more I look at these units, both my personal testing & the much broader and more detailed IPVM testing the more I feel that these units should be totally banned.

Any end user who wants their money back should be fully refunded.

Yes I work for a distribution company. Yes we have access to these devices. No we chose not to sell them due to ethical concerns.

I wholeheartedly agree people should be able to get their money back if a system doesn't work or is later shown to not work. And what's with these non-cancellable, eight-week leadtime orders? If the leadtime is that long, there's enough demand the manufacturer ought to be able to sell it somewhere else if in those two months the buyer needs to go elsewhere! My concern is that some of those manufacturers are just taking advantage of their buyers and distributors by pretending they need to do this.


They should all be sued and be forced to cease and desist. They're all frauds.

We did a similar test for a large manufacturer in June who wanted to know which of the five systems they'd bought would work (as well as how well ours, the Fever Inspect, would work), where we tricked one (expensive) "AI-powered" system from a competitor into scanning thin air using a mirror and it returned a reasonable temperature. Later we put a piece of tape over the thermal camera, and again it reported a reasonable temperature, which we duly recorded in the spreadsheet as 97.8F. All the rest (except ours, which reports faithfully what it sees) seemed to be pushing their outputs closer to 98.6F. Its shameful and fraudulent and reflects very poorly on the thermal industry.

Related Reports

Directory of 206 "Fever" Camera Suppliers on Aug 04, 2020
This directory provides a list of "Fever" scanning thermal camera providers...
Don't Be Fooled By Hot Water Bottle Fever Camera Demos on Aug 24, 2020
Fever camera salesmen like to fool buyers (and themselves) with hot water...
Fever Camera Sales From Integrators Surveyed on Jun 01, 2020
Fever cameras are the hottest trend in video surveillance currently but how...
Dangerous Hikvision Fever Camera Showcased by Chilean City on Aug 07, 2020
Deploying a fever camera outdoors, in the rain, with no black body, is...
Axis Compares Fever Camera Sellers to 9/11 on Sep 18, 2020
Axis Communications, the West's largest surveillance camera manufacturer, has...
Temperature Screening Is Ineffective, Says US, UK, Canada, Israel, And Ireland Health Leaders on Aug 25, 2020
Health leaders around the world are increasingly speaking out about the...
Hikvision Impossible 30 People Simultaneously Fever Claim Dupes Baldwin Alabama on Sep 01, 2020
The Alabama school district which spent $1 million on Hikvision fever cameras...
Alabama Schools Million Dollar Hikvision Fever Camera Deal on Aug 11, 2020
The Baldwin County, Alabama public schools purchased a $1 million, 144-camera...
Thermology Expert: "95-99%" Doing Fever Screening Wrong, Unjustified Compensating Algorithms "Insane" on Aug 27, 2020
A thermology expert tells IPVM "95 to 99% of people" are doing fever...
ADT: 'Fever' Cameras Are Medical Devices on Jun 15, 2020
While many manufacturers are avoiding admitting their 'fever' cameras are...
TVT Temperature Measurement Terminal Tested on Jul 23, 2020
While Dahua and Hikvision get the most attention for China temp products,...
FLIR A Series Temperature Screening Cameras Tested on Jun 04, 2020
FLIR is one of the biggest names in thermal and one of the most conservative....
Convergint Refuses To Fix Faked Fever Marketing, FTC Complaint Filed on Jun 19, 2020
Since Convergint has refused to fix their faked fever camera marketing, IPVM...
US Startup Fever Inspect Examined on Aug 03, 2020
Undoubtedly late to fever cameras, this US company, Fever Inspect, led by a...
The Next Hot Fever Detection Trend - $100 Wall-Mounted Units on Jul 06, 2020
The first wave of the booming fever detecting market was $10,000+ cameras,...

Recent Reports

Hanwha AI Object Detection Tested on Sep 28, 2020
Hanwha has added detection and classification of people, cars, clothing...
Favorite Access Control Manufacturers 2020 on Sep 28, 2020
200+ Integrators told IPVM "What is your favorite access control management...
New Products Show Fall 2020 Starts Tomorrow! on Sep 27, 2020
Tomorrow, IPVM's sixth online show will feature New Products from over 25...
OnTech Smart Services Partners With Google and Amazon To Compete With Integrators on Sep 25, 2020
A pain point for many homeowners to use consumer security and surveillance is...
The Future of Metalens For Video Surveillance Cameras - MIT / UMass / Immervision on Sep 25, 2020
Panoramic cameras using 'fisheye' lens have become commonplace in video...
Hikvision Sues Over Brazilian Airport Loss on Sep 24, 2020
Hikvision was excluded from a Brazilian airport project because it is owned...
China General Chamber of Commerce Calls Out US Politics on Sep 24, 2020
While US-China relations are at an all-time low, optimism about relations...
Verkada Disruptive Embedded Live Help on Sep 24, 2020
Call up your integrator? Have someone come by the next day? Verkada is...
IP Networking Course Fall 2020 - Last Chance - Register Now on Sep 23, 2020
Today is the last chance to register for the only IP networking course...
Drain Wire For Access Control Reader Tutorial on Sep 23, 2020
An easy-to-miss cabling specification plays a key role in access control, yet...
Norway Council of Ethics Finds Hikvision Human Rights Abuses "Ongoing" on Sep 23, 2020
Hikvision's involvement in "serious human rights abuse" in Xinjiang is...
IPVM Camera Calculator User Manual / Guide on Sep 23, 2020
Learn how to use the IPVM Camera Calculator (updated for Version 3.1). The...
Installation Course Fall 2020 - Save $50 - Last Chance on Sep 22, 2020
This is a unique installation course in a market where little practical...
SimpliSafe Business Security Launched Examined on Sep 22, 2020
SimpliSafe has launched "SimpliSafe Business Security" that the company...
FLIR CEO: Many New Fever Entrants "Making Claims That The Science Just Won't Support" on Sep 22, 2020
FLIR's CEO joins a growing number calling out risks with fever / screening...