EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: mbendzick on October 13, 2014, 06:36:59 pm
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Decided it was about time to join the forums - hello! Hopefully this could be a receptive crowd for a small rant about ebola scanning methods in airports. Yes, this is about test equipment...
I've seen far too many photos of inspectors holding up an IR thermometer from 3 feet away, putting the laser dot squarely on their hand, and presuming that will tell them if the passenger has a fever and thus ebola. No! The measurement cone is way too big, and the hand is going to be colder than the rest of the body anyway! Shine the laser on their forehead from 6 inches tops please.
I'm glad that these inspectors are checking to see if the wall behind the passenger has a virus that could cause it to bleed on me though. This lets me sleep at night.
I did see one photo of a customs inspection station with a full IR camera running - THAT might work. Put those in the airports by me please!
</rant>
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Decided it was about time to join the forums - hello! Hopefully this could be a receptive crowd for a small rant about ebola scanning methods in airports. Yes, this is about test equipment...
I've seen far too many photos of inspectors holding up an IR thermometer from 3 feet away, putting the laser dot squarely on their hand, and presuming that will tell them if the passenger has a fever and thus ebola. No! The measurement cone is way too big, and the hand is going to be colder than the rest of the body anyway! Shine the laser on their forehead from 6 inches tops please.
I'm glad that these inspectors are checking to see if the wall behind the passenger has a virus that could cause it to bleed on me though. This lets me sleep at night.
I did see one photo of a customs inspection station with a full IR camera running - THAT might work. Put those in the airports by me please!
</rant>
They installed full thermal camera's at the airports during the SARS breakout... I wonder what happened to those.
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http://i.telegraph.co.uk/multimedia/archive/02993/sierra-leone-scan-_2993195b.jpg (http://i.telegraph.co.uk/multimedia/archive/02993/sierra-leone-scan-_2993195b.jpg)
Yes!
http://www.laboratoryequipment.com/sites/laboratoryequipment.com/files/081914_lw_ebola.jpg (http://www.laboratoryequipment.com/sites/laboratoryequipment.com/files/081914_lw_ebola.jpg)
Fail!
http://i.telegraph.co.uk/multimedia/archive/03003/potd-ebola-2_3003356b.jpg (http://i.telegraph.co.uk/multimedia/archive/03003/potd-ebola-2_3003356b.jpg)
Yes!
http://media.npr.org/assets/img/2014/10/07/ap859823876424_wide-baee42dc790c1c3a509ab29129790fe93476dbb0-s4-c85.jpg (http://media.npr.org/assets/img/2014/10/07/ap859823876424_wide-baee42dc790c1c3a509ab29129790fe93476dbb0-s4-c85.jpg)
Fail!
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security theatre, enjoy the show.
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Yup, theatre. You probably would be better off simply taking each one, and then sitting them down in a room for 20 minutes then take a temperature measurement. That way the skin will reach equilibrium and those that are running a fever will stand out. Just doing it to a person who has just walked 200m from a plane will show elevated temperatures. If you are acclimated to central Africa you will feel cold and react accordingly when you hit Europe, with a cold face.
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when beuraucrats meet the real world :palm: :-DMM
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They installed full thermal camera's at the airports during the SARS breakout... I wonder what happened to those.
I wouldn't be at all surprised if Mike had one by now...
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I'm curious: how do they set the emissivity value in the IR thermometer?
Do they change it according to skin colour?
Do they use some dedicated instruments or they are standard units, such as my Uni-T?
I've done some tests with my IR thermometer, and I could not find an emissivity value that resulted in a correct reading of my body temperature, even when reading from a short distance. Am I missing something?
Best regards
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Core temp is almost always going to be different to skin temp, and as such you will never get a good reading. That is why you use a cavity like the ear, mouth or armpit, where you are closer to the core to measure. As to emissivity the human skin is pretty much going to be a close to ideal black body radiator irrespective of the skin colour.
You really would need to have a disposable ear contact and an ear thermometer to do screening, like used in hospitals to do temperature measurement. Least invasive, and at least going to give a very accurate reading of core temperature with a little care in use. Going to have a cost per use though in the ear pieces though, and they are cheap, but not low cost. The units themselves are definitely not cheap though, and need maintenance more than just changing of batteries.
Most accurate would be a probe that is placed into the core, though there you need a room, gloves, gel and a lot of trust in the operator.
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Core temp is almost always going to be different to skin temp, and as such you will never get a good reading. That is why you use a cavity like the ear, mouth or armpit, where you are closer to the core to measure. As to emissivity the human skin is pretty much going to be a close to ideal black body radiator irrespective of the skin colour.
I recall going to Taiwan during the SARS breakout and they had IR cameras at the airport. I don't think they look at exact temperatures but for people who are warmer than the rest.
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IIRC they also had a calibration target in the area set to emit IR which was the temperature of the average human. Then they looked for warmer than that for further screening. That way you do not have to rely on the camera needing to be accurate, it just had to be somewhat linear at temperatures between 30 and 45C.
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Both times I flew into O.R.Tambo International Airport (JNB) in Johannesburg, they had an IR camera aimed at the gate where they sort you to proceed to the next available passport-control window. This was long after SARS and years before the current Ebola outbreak. AFIK, it is a permanent feature of their security theater.
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Core temp is almost always going to be different to skin temp, and as such you will never get a good reading. That is why you use a cavity like the ear, mouth or armpit, where you are closer to the core to measure. As to emissivity the human skin is pretty much going to be a close to ideal black body radiator irrespective of the skin colour.
You really would need to have a disposable ear contact and an ear thermometer to do screening, like used in hospitals to do temperature measurement. Least invasive, and at least going to give a very accurate reading of core temperature with a little care in use. Going to have a cost per use though in the ear pieces though, and they are cheap, but not low cost. The units themselves are definitely not cheap though, and need maintenance more than just changing of batteries.
Most accurate would be a probe that is placed into the core, though there you need a room, gloves, gel and a lot of trust in the operator.
Better thermal cameras should be able to measure ear cavity temperature relatively easy.
Ear thermometers expensive? 40 to 80 usd and you get as good as you ever need for diagnosing fever.
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The problem is not in the thermometer but in measuring the temperature of over 100,000 people in one day each day. You need a system to be able to pick out suspects in a large group of people quickly.
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Core temp is almost always going to be different to skin temp, and as such you will never get a good reading. That is why you use a cavity like the ear, mouth or armpit, where you are closer to the core to measure. As to emissivity the human skin is pretty much going to be a close to ideal black body radiator irrespective of the skin colour.
I recall going to Taiwan during the SARS breakout and they had IR cameras at the airport. I don't think they look at exact temperatures but for people who are warmer than the rest.
:palm:
I was in Taiwan in the same period, they scan with a IR camera after customs in the airport but I think it was useless, to much people arrive at the same time.
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They had temp video monitors in customs of the boat from Hong Kong to Shenzhen last year.
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They had temp video monitors in customs of the boat from Hong Kong to Shenzhen last year.
We keep getting minor outbreaks of avian flu in HK, and each time we do they start using the cameras at the airport and the border crossings. When the risk abates they put them away. The per-lane temperature probes they had at immigration during the SARS outbreak would be 13 years old now. They were removed from both the China and HK sides as the immigration counters were refurbished.