With COVID19 pandemic affecting almost whole of the world, demand for thermal screening devices or thermal imagers have recently skyrocketed. Thermal Cameras are being used to detect fever or elevated body temperatures in a person while entering a building, office premises of a factory. But the question is, can thermal camera really detect fever, a medical condition in human body ?
A thermal camera can measure temperature or any object and that is all they are supposed to do. So, when they measure temperature of human body, they will measure temperature of their uncovered portion of the body. Normally, face, neck, hands and feet remain uncovered and thermal imager can measure temperature of these areas automatically when they come in the field of view (FOV) of the thermal camera.
Now if one sees medically, a fever is measured using a thermometer in the arm pit, inside ear or inside mouth and also some other areas which remain covered. So, in practice, it seems impossible to detect fever as a thermal imager will measure temperature of the human skin only.
Now next question would be, how accurate are the measurement of thermal imagers are! Before COVID19, most thermal imagers had accuracy of +/-2 degree C accuracy. But post COVID19 pandemic, the accuracy of thermal imagers have increased to +/-0.3Degree C. So, one can safe, Thermal Imagers are now accurate enough to detect fever provided it gets to measure the right area of the human body!
Are Thermal Imagers useful in fever screening ?
I would say, it is very useful for the following reasons:-
- It is already difficult to infer fever or any medical condition for that matter without licensed medical practitioners. Thermal Imager is supposed to sense temperature in human body and it does well in that.
- Based on the temperature provided by Thermal Imager or Thermal Scanners, its upto the competent authority to decide the next course of action if anyone has high body temperature.
- Its not practical to read temperature of everyone by a medical practitioner one by one, as its very time consuming, risky for the medical practitioner as well as contrary to social distancing, a tool to fight infection. Measuring human body temperature using Thermal camera is automatic, fast, accurate. Human intervention is needed only when elevated body temperature is detected.
- If used with high resolution thermal camera and wide angle lens, a single thermal camera can scan a large area for any one for high body temperature. When used with a visual camera, this could identify the person with high body temperature for further investigation.
- Using thermal camera is easy as it is goes with normal business process. No training is needed. Also software with thermal cameras can have many report and analytics which is helpful.
So, my personal opinion would be, thermal imager should be the first step in isolating person with high body temperature for further investigation. Thermal Camera is the only tool right now which can help screening large number of people. This is particularly useful to screen people to enter factories, building or office premises. There are not many such fever detection systems, but post-Covid19, most thermal imaging companies have developed such fever screening systems.