On the proposal of quantitative temperature measurement using two-colored technique combined with several infrared radiometers having different wavelength bands

Infrared Thermography has been widely used to visualize a two-dimensional temperature field for various engineering applications. In general, the conventional technique can not be directly applied to quantitative temperature measurement for glossy metal surfaces under near-ambient conditions because the influence of the reflected energy becomes severe on the temperature measurement. When necessary to measure temperature quantitatively, an appropriate calibration having complicated formalities should be performed. In this paper, therefore, a technique of measuring temperature is proposed under near-ambient conditions by combining several infrared radiometers having different wavelength bands to make the two-colored technique which is not needed to practice any temperature calibrations. The respective sensors concerned have a selective wavelength of several μm in width in the range of 2-13 μm. The applicability including a series of equations proposed is confirmed using the numerical simulation merely to allow a parametric study of how the result varies for different values of emissivity indicated with a pair of infrared radiometers. The experimental investigation is also performed to estimate a measurement error of the technique proposed. The technique has a feature that we can perform quantitative temperature measurement without presuming any emissivity and reflectivity. (author)