This expert-system multiwavelength pyrometer overcomes many of the limitations associated with traditional pyrometers and has provided a wealth of information not previously available.
The Spectropyrometer was developed to address the flaws of traditional radiation pyrometry that lead to inaccurate temperature measurement. Traditional pyrometers require the operator to provide emissivity information that is difficult to obtain. Emissivity values for many material compositions cannot be found in reference publications, and if the exact composition is found, the reported range of emissivities is often too broad to dispel the uncertainty. Ratio pyrometry was an earlier attempt to address these problems. The intent was to cancel out the contribution of emissivity by dividing the intensities at two wavelengths, but for ratio pyrometry to return accurate temperatures, the emissivity must be the same at both wavelengths, and this is not always true. Therefore, some devices provide a "non-grayness" adjustment, again requiring the operator to know the emissivity, but now at two discrete wavelengths. Compounding the problem, ratio pyrometers typically use fairly broad wavelength ranges (despite referring to the two wavelengths in the singular), and anything that affects the intensity within these ranges affects the temperature.