Human Temperature Measurement with Infrared Cameras

[acardoso]

  03_2012 Cardoso.pdf (Size: 165.47 KB / Downloads: 195) At April 26th of the current year I presented a paper at InfraR&D 2012 during the Hannover Messe about a technic developed by me to measure temperature in Humans with infrared cameras

[cruel1]

(06-21-2012 10:03 AM)acardoso Wrote:  At April 26th of the current year I presented a paper at InfraR&D 2012 during the Hannover Messe about a technic developed by me to measure temperature in Humans with infrared cameras

Very informative. Thank you.

[acardoso]

See also
Screening fever, a new approach. This new paper is aimed to the problems at ISO recommendation and how can be overcame.

[acardoso]

Since this technic is old knowledge on a new field of application, all technology needed to apply it was developed before. This means, thermograms older then the settling of the technic can be used to measure temperature. The thermogram below is older than the technic, however temperature of this car racing pilot in the past, can be know now. Put the emissivity to 1, and check if MFOV is smaller than the opening of the external auditory meatus.
   
Always try to take thermograms for human temperature measurement positioned 10 ° to the back, this will maximize the size of the opening of the external auditory meatus
   

[acardoso]

3D images of both meatus. Note the huge increase of radiation where there is nothing, the opening of the meatus
               

[acardoso]

A possible layout of a station for self-screening fever

A Flir X6x0 with a 12° lens
A tripod
A TV set on a stand

2 hours to setup

    Location: https://maps.google.pt/maps?q=CATIM-+Cen...T&t=h&z=16
The camera is at a distance of the 257 cm (8' 5.2") from the marker and 58 cm (1' 10.8") into the back, more or less 12°45'. This layout can measure persons from 1,52 cm (4' 11.8") to 187 cm (6' 1.6") without intervention of an operator

SolidWorks Model of the station
https://docs.google.com/file/d/0B-8b5ujw...sp=sharing
Movie from the SolidWorks model
https://docs.google.com/file/d/0B-8b5ujw...sp=sharing


   
Instructions set in English
https://docs.google.com/file/d/0B-8b5ujw...sp=sharing

[acardoso]

And now, the movie
Less bit stream: https://docs.google.com/file/d/0B-8b5ujw...sp=sharing
Full quality: https://docs.google.com/file/d/0B-8b5ujw...sp=sharing

[acardoso]

Youtube link
http://www.youtube.com/watch?v=2ijEh1HNLxg

[acardoso]

Abstract of the oral presentation "The illusion of a black body at Human ear and the Human temperature measurement", done at TEMPMEKO 2013 (http://www.tempmeko2013.pt/) during the session "Radiation Thermometry 2"

The use of the inner canthus or the insertion of probes in Human ear or any other technic involving contact thermometers to determine core temperature in Humans, and to be used as a reference, can be compromised by wide number of factors that can lead to faulty measurement.
Despite at inner canthus the ophthalmic artery flow beneath, cerebrovascular disease at internal carotid artery will diminish flow at downstream arteries, and consequently, the amount of heat dissipated at inner canthus and the temperature at surface, drops. Accumulation of mucus discharge at inner canthus will enhance the dropping. Thermographilly speaking, the area has an emissivity very well determined, 98 %, which implies, besides this accuracy, the determination of reflected apparent temperature.
Clinical thermometers have to be kept disinfected, or diseases like Flu, Hepatitis, Herpes, Tuberculosis and other sweat related will propagate. Besides, since they are contact thermometers, the temperature the user reads, is the internal sensor temperature and not the one of the patient.
Temporal Artery Thermometers, like the clinical one, are contact thermometers. Besides all the problems of the above one, they have accuracy problems related to positioning. If not proper positioned over the temporal artery, the reading is faulty.
The ear thermometer is non-contact, as well as non-ecological. Each measurement generates a plastic waste; the plastic probe cover. It has problems related to emissivity; the user has to aim to the ear drum, otherwise he will read the radiation on the walls the external auditory meatus with an angle less than 45°. At the interior of the external auditory meatus, the emissivity has a value of 98%. When a probe at room temperature is inserted, reflected temperature will be effective and cause a measurement error, even if the probe is properly aimed to the ear drum. Only every 3rd or 4th reading produces correct values.
Even the insertion of a Pt100 or a thermocouple on the Human ear, due to the lack of flow inside external auditory meatus and good level of insulation provided by still air, contribute to a faulty measurement. On this technic the wires of the thermometer are another problem. Since they are metal, and metals are good thermal conductors, the wires will act as thermal drains, compromising the final value.
On the other hand, external auditory meatus are wave-guides and need to be kept at constant temperature; otherwise the velocity of sound propagation will vary along its length, creating echoes inside of themselves. In this way, external auditory meatus are isothermal cavities and due to its geometrical configuration, an illusion of black body is always present at the interface with the exterior. Unlike the tympanic thermometers which are affected by crooked meatus or wax, because they have to "see" the eardrum, thermographic cameras do not have the accuracy compromised, provided that, the problem is not visible from the outside. In all other situations, the external auditory meatus, when observed from the outside, always have an emissivity of 100 %, relieving the measurement from determination of the reflected apparent temperature.
This technic allows the set of self-screening station, working without operators in fully automatic mode, where persons will stand in front of a TV set and will see their temperature. Or in airports, where operators will be beyond monitors, controlling persons walking in line.

[frankliebmann]

(10-28-2013 09:36 AM)acardoso Wrote:  Abstract of the oral presentation "The illusion of a black body at Human ear and the Human temperature measurement", done at TEMPMEKO 2013 (http://www.tempmeko2013.pt/) during the session "Radiation Thermometry 2"

I enjoyed your presentation Antonio. It was great to meet you.