Environment determines the accuracy of measuring temperature of infrared forehead thermometer

Infrared thermometers are widely used in screening hot people in public places due to their non-contact and short measurement time. In addition to the frontal temperature gun, the common non-contact infrared thermometers are ear thermometers and infrared cameras. The temperature measurement principle behind them is the same.

Ji Yang, a researcher at the Institute of Semiconductors of the Chinese Academy of Sciences, explained that any temperature object will have thermal radiation, which is actually electromagnetic waves. Infrared radiation, also known as infrared or infrared light, is a type of electromagnetic wave. The higher the temperature of the object, the greater the infrared radiation power; on the contrary, the lower the temperature of the object, the smaller the radiation power. The infrared thermometer can infer the temperature of the human body by measuring the power of infrared radiation.

There are two types of body temperature, a relatively constant and uniform core temperature deep in the body and a surface temperature close to the skin surface. The ear thermometer measures the temperature of the tympanic membrane in the ear. The temperature of the tympanic membrane and the pulmonary artery are very close, so it is considered to be a reliable indicator of the deep temperature of the human body. The forehead gun measures the temperature of the skin on the forehead.

If it is in a stable indoor environment and the quality of the equipment is ruled out, there is almost no difference in the accuracy of the ear thermometer and the forehead thermometer. However, the measurement results of the ear thermometer can be included in the clinical signs data, but the frontal thermometer is not. "The reason is simple. The temperature of the skin surface is easily affected by the external environment. Changes in the background temperature will cause the skin temperature on the human body to change, which will affect the accuracy of the measurement." Liu Jianguo, a researcher at the Institute of Semiconductors, Chinese Academy of Sciences, said.

Compared with ear thermometers and forehead thermometers, thermal imaging cameras are generally suitable for places with very dense crowds such as airports, train stations, subways, shopping malls, etc., because it can meet the needs of mass non-inductive monitoring and screening within a certain distance. Efficiency is higher, and of course the price is the most expensive.

"And its most fundamental flaw is the same as the front temperature gun. It has poor adaptability to complex environments and has the problem of inaccurate measurement." Liu Jianguo said that if he just walked out of an air-conditioned car or passed outside in the cold, their test As a result, there will be a large deviation from the true core temperature of the human body.