Is an infrared camera harmful to the human body?
The thermal measurement principle of a thermal imager is to passively receive infrared radiation from an object for imaging and temperature measurement, and all objects exceeding absolute zero (-273.15 degrees Celsius) emit infrared radiation.
Therefore, using a thermal camera to measure body temperature is not harmful to the human body.
Airports, train stations, and other places, why use infrared cameras for temperature screening?
Infrared camera is a non-contact temperature measurement. It only needs a person to appear in the thermal imaging lens to measure the temperature. The thermal imaging camera has a fast response speed and can measure all temperatures in a wide range at the same time. Huge places, using a thermal camera to screen passenger temperature is very efficient.
The thermal camera industry standard allows a temperature difference of plus or minus 2 degrees Celsius within 100 degrees Celsius. Is it accurate for screening body temperature?
Some people are skeptical about using a thermal imager for body temperature screening. The reason is that the industry standard for temperature accuracy of a thermal imager is plus or minus 2 degrees Celsius within 100 degrees Celsius.
In fact, the thermal imager is still very accurate to measure human body temperature, and the error is generally a few tenths of a degree Celsius.
Moreover, as a screening, it is not necessary to accurately measure the body temperature, and continuous temperature stability and consistency are needed. Imagine that if everyone's body temperature is about 34 degrees Celsius (the body surface temperature is generally not 37 degrees Celsius), then someone's body temperature is 37 degrees Celsius. Does he have a fever?
Taking the FOTRIC thermal imager as an example, it can be seen in the test report of the "China Electric Power Research Institute" that the error fluctuation of 49.8 degrees Celsius in the continuous 2 hours test is small, and the temperature in the picture is consistent with each The measurement of the same temperature at the part is basically the same, so that the body temperature measured by it is referenced and can be used as a body temperature screening.
In addition, many thermal imagers on the market have multi-color dynamic imaging functions, which can greatly enhance the subtle temperature difference imaging effect of specific targets in complex scenes, which is conducive to finding feverish people.
In addition, the area alarm function can be used to notify workers in the form of audible and visual alarms when a high temperature point of heat is captured in each area.
How does the thermal imager detect body temperature?
First, choose a suitable testing place. The first is to avoid the influence of ambient temperature on the human body temperature to improve the temperature measurement accuracy. For example, low outdoor temperature in winter will reduce the human body surface temperature.
The second is to control the flow of people. When a feverish person is found, he can find himself in time for follow-up work.
Secondly, you can first find 5 to 10 people with normal body temperature to measure the body temperature, then take the average value and increase it by about 2 degrees Celsius as the warning temperature to set the alarm threshold for the thermal imager.
Finally, at the operational level of the camera, the following points should be noted:
The first point is the setting of parameters such as emissivity. The long-wave infrared emissivity of human skin is 0.98. The emissivity of the thermal imager can be set to 0.98, the reflection temperature can be set to the ambient temperature, and the ambient temperature and humidity can be set normally. The test distance can use the default value of 1m, or it can be set to 2m, 5m or even 10m, because the short-distance test has a very small impact.
The second point is that you need to focus clearly and you can visually see the skin surface such as the forehead.
Third, pay attention to the temperature measurement range and select a suitable range for a small range. At present, most thermal imaging cameras should choose -20 degrees Celsius to 120 degrees Celsius, or -20 degrees Celsius to 150 degrees Celsius.
