Preface on "Advanced Infrared Technology and Applications - AITA 2021"

A new emissivity measuring apparatus based on infrared thermal imager is developed for measuring the emissivity of materials with wavelengths from 8 to 14 μm in the temperature range of 373 K to 873 K. The apparatus consists of four main parts: A heating unit for precisely controlling the temperature of sample, a thermal radiation imaging measurement unit for collecting signals of background and sample, a running unit for adjusting the orientation and focal length of between the lens and sample, and a data processing unit for calculating emissivity of sample. To verify the performance of this apparatus, unpolished and polished aluminum with 120 CW, 240 CW, 360 CW sandpaper are measured at 373 K, 473 K, 673 K, and 873 K. The measurement results are basically consistent with that of Fourier transform infrared spectrometer (FTIR spectrometer), and the combined standard uncertainty is 2.49 %, not more than 3 %.