How do I use a non-contact infrared scanner?

Q. What are the uses of an infrared thermal scanner?

• A. Infrared scanners are used to measure temperature of the human body, machine surfaces, concrete surfaces etc. It provides an estimate for surface temperature of a body.

Q. What is an IR scanner?

• A. IR or Infrared Scanner is a sensor device that receives IR radiation from the surface of a body ( skin in the case of a human being) and estimates the temperature of human skins ( like Forehead, Wrist, Forearm etc). This is used to screen people with Fever.

Q. Difference between the infrared scanner and thermal scanner?

• A. They are essentially the same thing since most of the non-contact thermal scanners are IR scanners. But one can also use a contact thermometer ( mercury or semiconductor) as well to screen Feverish people.

Q. How do I use a non-contact infrared scanner?

• A. The use of an infrared scanner can be very tricky and requires fundamental knowhow of how IR non-contact thermometers work. Without proper guidance, a non-contact thermometer may produce a false reading. There are six basic rules to remember while trying to use a non-contact IR thermometer:

1. An IR thermometer scans radiation from the exposed area of the skin which can be the forehead, teardrop, fist, or wrist, etc.
2. Fever is defined as a rise in core body temperature above 100.4F. Skin temperature rises with increasing core body temperature only if the skin is not exposed to extreme hot or cold environment. The best ambient to scan is always between 20C and 30C (70-90F) or indoor ambient. Also, different areas of the skin differs from the core body by a constant amount. For example, the forehead will be 1-2F less than the core body while for the fist, the difference is slightly larger ~ 1-4F. But if a person is exposed to windchill and forehead/fists are not covered, then this difference between skin and forehead can exceed more than 10F.
3. Skin below which there are arteries (better blood circulation) are the closest to core body temperature and therefore are more preferred areas for scanning since blood carries the heat from the body to the skin.
4. However, since fever screening devices are used mostly to screen the people who are walking from the parking lot to a nearby reception area, the best area of the skin to scan is the middle of the forearm since that is normally covered during winter.
5. Reading will be consistent and good if the sensor is within 4-6 inches. Beyond this range, reading will be unreliable due to bad signal to noise ratio.
6. It is advisable to calibrate the non-contact thermometer with a NIST traceable standard blackbody radiator for better reading.

Q. Do I need to be a trained thermographer to screen temperature?

• A. No special training or certification is needed, but please do remember the following CDC guidelines:
  
  The Equal Employment Opportunity Commission (EEOC) gave employers the green light to take employees' temperatures to try and ward off the spread of the coronavirus in guidance from earlier this year.
  
  "Generally, measuring an employee's body temperature is a medical examination," the EEOC stated. The Americans with Disabilities Act (ADA) prohibits medical examinations unless they are job-related and consistent with business necessity. However, because the Centers for Disease Control and Prevention (CDC) and state and local health authorities have acknowledged community spread of COVID-19, the respiratory illness caused by the coronavirus, and have issued related precautions, "employers may measure employees' body temperature.
  
  Thermal imaging cameras are designed to provide accurate thermal recordings based on heat signatures. They translate thermal radiation, which is normally not visible to the naked eye, into visual images with different colors indicating heat levels. For example, dark red stands for abnormally high temperatures, whereas blue shades indicate cooler temperatures. Therefore, the thermal imaging results are fairly simple to read and anyone can be given some basic training to use these devices and can identify normal from abnormal temperatures.

Q. How to use a thermal imaging camera?

• A. For reliable temperature reading, a thermal imaging camera must have at least 5000-10,000 pixels. This is because the only area of the face that is close to core-body temperature is the teardrop. Unless the camera has high pixel density, there is no way, teardrop temperature can be recorded due to poor resolution. Forehead scanning will be highly misleading since, during winter, the forehead will be much colder. Also, scanning should be one person at a time and there should be an optical camera to target the teardrop area.

Q. How does thermal imaging work?

• A. Thermal imaging uses IR (Infrared) photoreceiver which detects radiation from the human body in the wavelength range between 9 to 14 micron. The human body is a near-perfect blackbody radiator ( emissivity .96-.99). When a Matrix array of IR Photodetectors are used to capture the radiation from the face, based on the focal plane of each IR Photodetector (which has a focusing mechanism), the temperature of each pixel of IR image can be estimated by comparing with ideal blackbody radiation curve. The curve peaks at a particular IR wavelength that is indicative of the temperature of the radiating surface. The system has a digital filter and a look-up mechanism to correlate between the blackbody curve and skin temperature.

Q. How much is a thermal imaging camera?

• A. Thermal imaging camera starts from $10,000USD and very good ones can be above $30,000.

Q. Why are thermal imaging cameras so expensive:

• A. This is because of the fact a good thermal imaging camera needs more than 5000 IR Pixels and a good optical camera to focus on. Technology is complex. A Good thermal camera can start from $10,000 onwards.

Q. What is the best place to take the temperature with an infrared scanner?

• A. The best place to take the temperature with Infrared is the middle of the forearm. The Forehead is close to core body temperature but it is useless in North American winter when the guest has to walk a few minutes and forehead skin temperature may drop below 94F. Also scanning Forehead is difficult if an automated IR scanner is used. The Fist is a better alternative to Forehead for automated scanning. But the middle of the arm works better in winter since it is covered from outside cold weather.

FeverWarn - Series 100 & 200 Unboxing

FeverWarn - Installing FeverWarn for iOS

FeverWarn - Onboarding and Account Creation for Android