Harigovindan S, Sobha K S
Appl Opt. 2000 May 20;39(15):2461-6. doi: 10.1364/ao.39.002461.
What is to our knowledge a novel infrared thermometer (IRT) for remote measurement of the temperature rise (-20-100 K) above the variable ambient (270-320 K) of a distant object is described. A radiation-balancing method is successfully extended to the near-ambient temperature range by variation of the temperature of a built-in blackbody, until the radiation from it equals the radiation from the source, so that its temperature is proportional to that of the source. Another feature believed to be novel is simplifying the design by elimination of the need for cooling the blackbody for subambient temperature range by use of a second blackbody, strategically located, which is heated to achieve radiation balance. Detailed theoretical analysis is given, showing that the IRT can measure remotely the total emissivity or even the electric current or voltage. Resistive inserts are proposed for improving the accuracy of current measurement. A method is proposed for simultaneous remote measurement of absolute temperature and emissivity by variation of the heating current and the aperture of the blackbody for radiation balancing in two bands so that prior knowledge of the object's emissivity is not needed.
本文描述了一种据我们所知的新型红外温度计（IRT），用于远程测量远处物体在可变环境温度（270 - 320K）之上的温度上升（-20 - 100K）。通过改变内置黑体的温度，辐射平衡方法成功扩展到近环境温度范围，直到其辐射等于来自源的辐射，从而使其温度与源的温度成比例。另一个被认为是新颖的特点是，通过使用第二个精心放置的黑体来加热以实现辐射平衡，从而无需在低于环境温度范围冷却黑体，简化了设计。给出了详细的理论分析，表明IRT可以远程测量总发射率，甚至可以测量电流或电压。提出了电阻插入件以提高电流测量的精度。提出了一种方法，通过改变加热电流和黑体的孔径以在两个波段实现辐射平衡，从而同时远程测量绝对温度和发射率，这样就无需事先了解物体的发射率。
