# Epidemics and thermal cameras

If thermal cameras (TC) could be cheap, they could be located in many buildings and the can have huge efect on reduction of epidemics spreading. (Do you agree?)
One TC cost around 10000$. What is the problem for world consensus for research for cheaper thermal cameras? It is cheaper and with less side effects that new vaccines. ## Answers and Replies berkeman Mentor If thermal cameras (TC) could be cheap, they could be located in many buildings and the can have huge efect on reduction of epidemics spreading. (Do you agree?) One TC cost around 10000$. What is the problem for world consensus for research for cheaper thermal cameras? It is cheaper and with less side effects that new vaccines.

What mechanism are you alluding to? Do you have scientific studies of thermal imaging and various diseases that you can point us to?

Andy Resnick
I agree with berkeman- what is the correlation between thermal imaging of fully-clothed people and contagious disease?

Andrew Mason
Homework Helper
I agree with berkeman- what is the correlation between thermal imaging of fully-clothed people and contagious disease?
Fever, perhaps?

AM

For the last epidemic swine flu they are used in airports. Also some last epidemics. If they were used more frequently in more buildings, sick people were isolated sooner. And this is a key factor.

I have no study, but let us imagine...

"fully-clothed people" The face is enough.

Reducing of fever is also important - for beginning.

Last edited:
My first impression is that it sounds a promising idea.More research is needed.

Danger
Gold Member
If W is any indication, you'd end up quarantining a lot of menopausal women. :uhh:

My question is also: What gives high price to thermal cameras?

f95toli
Gold Member
My question is also: What gives high price to thermal cameras?

The sensors are quite expensive. And the really good ones are built using some rather "exotic" materials (some unusual semiconductors etc) which are both expensive in themselves and difficult to manufacture (I suspect the yield is quite low).

I've read that while it worked for SARS it won't work well for this swine flu epidemic. The reason being that in case of SARS, you would only start to spread the disease after the disease had manifested in you, while in case of swine flu, you can start to infect others before you are ill.

So, if you get the virus, the virus starts to multiply in your body. You will get a fever 3 to 6 days after being infected. But already after a day of being infected you can start to spread the virus to other people.

This is true for flu in general (although the incubation time for ordinary flu is a bit less, I think). This is part of the explanation why flu spreads better in the winter than in the summer. In the winter you'll tend to sneeze and cough more often (due to colds or simply because in cold weather you make more mucus that you want to discharge). This then makes it easier for you to spread flu if you are infected when you are not yet ill.

russ_watters
Mentor
I'm calling BS on the entire concept. I realize it was done, but I can't see how it could possibly be done with any effectiveness at all. Physiological differences, measurement differences, and measurement precision make accurate body core temperature readings via skin temperature measurement impossible. Here's an article about it: http://www.hkmj.org/article_pdfs/hkm0606p242.pdf
There are few retrospective evaluations of NCIRTIS’
use in blind mass fever screening. During the SARS
epidemic of 2003, thermal scanning of over 35 million
international travellers entering Canada, China, Hong Kong
SAR, and Singapore did not pick up a single SARS case.
Screening at exit from Canada, Hong Kong SAR, Taiwan,
and Singapore of over 7 million people also failed to find a
single SARS case.4

russ_watters, if it is so, camera is really not effective. But it need improvements and it maybe one day it will better. The problem is probably the emission factor? Maybe two color thermal cameras? Why they do not exist?

Count iblis, But maybe there are also other technological solutions... I never give up. Maybe faster cheap analyses of mucus, urine, etc. Still ever more friendly than vaccination.
But I addmit more futuristic than thermal imaging.

Last edited:
russ_watters
Mentor
russ_watters, if it is so, camera is really not effective. But it need improvements and it maybe one day it will better.
To be a little clearer than I was before, there are three separate problems:
1. People are different.
2. Environments are not consistent.
3. Cameras are not precise enough.

So the camera was only one of the three problems.
The problem is probably the emission factor? Maybe two color thermal cameras? Why they do not exist?
"Color" is a function of wavelength as interpreted by our eyes. Since our eyes don't see into the infrared, there is no "color" to speak of (unless you call IR itself a "color"). The images produced by these cameras are mapped to colors we can see, ie "false color" images.

DaveC426913
Gold Member
Yeah, I'm with Russ. Before you worry about what kinds of cameras you'd need, you first need to demonstrate that it's even possible in principle to pick out an ill person under the wide-ranging and continually-changing conditions of the real world. I'm just not sure it's possible. I'm not sure that simple external body temperature is any reliable indicator of illness. The range for detection is probably swamped by normal human variance.

But it would be good to see some research.

russ_watters
Mentor
Somewhat related, here's an article that questions the accuracy of forehead thermometers:
For their study, Crandall and his colleagues had 16 healthy adults wear special wetsuits that were gradually heated to raise their core body temperature. Their temperatures were repeatedly measured with a temporal scanner and with the ingested pill.

Before the suits were heated up, readings from the temporal scanner and pill generally matched up. But after 30 minutes of heat, readings from the scanner actually fell, despite the fact that volunteers' core temperature was climbing.
http://www.reuters.com/article/scienceNews/idUSPAR05104120070810

I can think of a reason for that - when your body needs to dissipate heat more, it may not necessarily dissipate it evenly. Ie, if your whole body sweats but your forehead is open to the air and your body is not, your forehead will dissipate heat faster and therefore the skin surface temperature would drop.

It sounds like a thorny problem exponent but there may be a solution and it is certainly deserving of some research.May I suggest that you start by looking at the symptoms of the disease and which of these may display their prescence externally.You have mentioned urine so are there changes in this and perhaps changes in sweat?Do the changes in urine and sweat also result in changes to their odours and the light reflection characteristics of the skin?
I have just imagined a sniffer dog running weaving its way through the passengers sniffing at peoples groins.I'ts not necessarily a crazy idea because dogs have very acute senses of smell.There's no need to worry about the dog taking an occasional bite because it will be wearing a surgical mask.

Can anyone tell me where to order my designer label surgical mask?Can I get one from Calvin Klein?

To be a little clearer than I was before, there are three separate problems:
1. People are different.
2. Environments are not consistent.
3. Cameras are not precise enough.

So the camera was only one of the three problems. "Color" is a function of wavelength as interpreted by our eyes. Since our eyes don't see into the infrared, there is no "color" to speak of (unless you call IR itself a "color"). The images produced by these cameras are mapped to colors we can see, ie "false color" images.

2 color camera is a tehnical term. It means that a pyrometer measures at two frequencies, so it can determine also emission coefficient (EC). Common pyrometers works on one frequency and we set their EC. The same is at thermal cameras.

Otherwise it is interesting use of thermal camera at doctors. Temperature of naked person can give a lot of informaction, the question is if we can get useful information from it.

And really if it is possible to analyse also other informations as odours, reflection caracteristic of skin, this can be a step forward ....
Even some peoples (the best womans) have good sense of smell.

DaveC426913
Gold Member
I can think of a reason for that - when your body needs to dissipate heat more, it may not necessarily dissipate it evenly. Ie, if your whole body sweats but your forehead is open to the air and your body is not, your forehead will dissipate heat faster and therefore the skin surface temperature would drop.
I'm not sure this makes sense. If your forehead is dissipating heat faster, then it will be picked up as radiating more heat by the scanner, period.

I'm not sure this makes sense. If your forehead is dissipating heat faster, then it will be picked up as radiating more heat by the scanner, period.

I am guessing that the heat losses by radiation are very small when compared to the heat losses by convection and sweat evaporation.Perhaps the convective losses could be detected with the Schlieren effect

russ_watters
Mentor
2 color camera is a tehnical term. It means that a pyrometer measures at two frequencies, so it can determine also emission coefficient (EC). Common pyrometers works on one frequency and we set their EC. The same is at thermal cameras.
Oh, sorry, didn't realize that.

russ_watters
Mentor
I am guessing that the heat losses by radiation are very small when compared to the heat losses by convection and sweat evaporation.Perhaps the convective losses could be detected with the Schlieren effect
Not small, but the fraction does drop when we sweat, as sweat vastly increases the heat loss by evaporation/convection. And that's assuming the skin surface temperature stays constant. Like I said, the skin surface temperature may rise on some parts of your body (covered parts, in particular) while dropping on others.

It may also be more a matter of temperature gradient: your body is trying to maintain a constant internal temperature, not a constant skin temperature, so if your heat dissipation rises, your internal temperature stays (roughly) constant, while the temperature gradient across your fat and skin gets steeper to dissipate more heat. At the same time, dilation of the blood vessels brings more warm blood closer to the surface (potentially for the opposite effect).... Getting too far into the physiology starts to get beyond my expertise, though.

Last edited:
This discussion suffers from lack of real data.

Mentor Edit: Please feel free to share any valid information you have. Links to sites selling your products defeats the purpose of having a meaningful discussion *here*.

Last edited by a moderator:
[spam deleted]
BTW, in the Infrared there is not much difference between humans except for their temperatures and temperature distribution.

In the 8 to 14 micrometer waveband, for instance, we are all effectively pretty much the same and "black" with spectral emissivity mostly greater than 0.95.

I agree with the critique that "2 color" is a poor term used in Thermal Infrared Radiation Thermometry. Blame no-nothing marketing types! A more precise term is "Two Waveband Radiation Thermometry", with the proviso: "used in the Ratio mode", the most common type of multi-waveband Radiation Thermometer (there are other modes).

Such devices do exist in the market but they are not needed in this use, not cost justified (they are very, very expensive).

Finally, the quoted critique of the method as effectively being worthless; it a mis-stated fact. SARS cases and Dengue fever cases have been detected with Thermal Infrared Imaging Cameras in China and Taiwan and the info is in the literature. If anyone would like references let me know at grp [at] mrpyto [dot] com.

Last edited by a moderator:
So what is price of common thermal cammera (in airports for sars...) and multi-waveband one?

More precise estimation of quality of termal camera is, how many people with higher body temperature were found, not people with SARS were found.

Last edited:
Thermal Camera Systems designed for use in human body temperature screening are complete systems and start with prices of about $(US) 30k. Dual Waveband cameras without additional system components and special software start in the$(US) 100k range.

But as mentioned earlier, there is no need for dual wavebands since the spectral emissivity of humans is essentially black in the waveband region from 8 to 14 micrometers. In fact, it's nearly flat over a much wider spectral range from the near IR, about 1.5 micrometers, to well beyond 20 micrometers in the "long wave" portion of the IR and mimics, not surprisingly, that of water, as was reported some 70 years ago by J, D, Hardy at Yale University.