– An almost ideal blackbody, realizes accurate conversion between temperature and infrared radiation level –
Researchers) AMEMIYA Kuniaki, Group Leader, SHIMIZU Yuhei, Researcher, Applied Optical Measurement Group, Research Institute for Physical Measurement
- Development of a flat-plate blackbody device that enables calibration of thermography readings without influence from ambient
- Fabrication of a high-emissivity, nearly perfect blackbody material by surface micro-processing
- Expected to contribute to preventing the spread of infectious diseases by improving the reliability of non-contact body temperature measurement
Prototype flat-plate blackbody device (left), electron microscope image of blackbody plate surface (center), and example of thermal image (right)
Body temperature measurements are being carried out at borders and in places where many people gather as a measure against emerging infectious diseases. In particular, thermography that visualizes the temperature distribution based on the infrared radiation from an object can measure body surface temperature without contact, which is effective in reducing the burden and risk at quarantine stations. However, non-contact temperature measurement technology including thermography has many points for caution, such as susceptibility to environmental factors. Therefore, it is recommended to use a flat-plate blackbody device as a temperature reference for on-site correction of measurement error. The conversion between temperature and infrared radiation level is based on Planck’s law of blackbody radiation. The blackbody material of the flat-plate blackbody device needs to have a high infrared emissivity as close to 1 as possible to achieve sufficiently small uncertainty without influence from ambient. However, conventional blackbody materials have issues in achieving both high emissivity and durability, and there were no flat-plate blackbody devices with sufficient emissivity.
In collaboration with CHINO Corporation, AIST researchers developed a flat-plate blackbody device that serves as a precise and accurate temperature reference for thermography for non-contact body temperature measurement.
The collaboration team fabricated a black-resin material having a surface microstructure that is extremely close to an ideal blackbody (emissivity of 1) in a range of infrared wavelengths. On the basis of Planck’s law, the flat-plate blackbody device can precisely and accurately correlate temperature in the body temperature range and infrared radiation level. This enables thermography performance tests, evaluation of error factors such as the influence of the measurement target and the surrounding environment, and on-site calibration of temperature readings. Precise and accurate measurement of body surface temperature by thermography is expected to contribute to improving the reliability of non-contact body temperature measurement.