**Novel Air Temperature Measurement Using Midwaveȱ ȱ Hyperspectral Fourier Transform Infrared Imaging in theȱ ȱ Carbon Dioxide Absorption Band**

**Sungho Kim**

Department of Electronic Engineering, Yeungnam University, 280 DaehakȬRo, Gyeongsan,ȱ ȱ Gyeongbuk 38541, Korea; sunghokim@ynu.ac.kr; Tel.: +82Ȭ53Ȭ810Ȭ3530

This paper presented an approach to measuring air temperature from mid-wave hyperspectral Fourier transform infrared (FTIR) imaging in the carbon dioxide absorption band (between 4.25 and 4.35 mm) where the accurate visualization of air temperature distribution can be useful for various thermal analyses in many fields such as human health and the heat transfer of local areas. The proposed visual-air temperature (VisualAT) measurement is based on the observation that the carbon dioxide band shows zero transmissivity at short distances. Based on the analysis of the radiative transfer equation in this band, only the path radiance by air temperature survives. The brightness temperature of the received radiance can provide the raw air temperature and spectral average followed by a spatial median–mean filter that can produce final air temperature images.

remotesensingȬ13Ȭ01249Ȭv2
