Radiometric versus thermometric calibration of IR test systems: which is best?

摘要

Radiometric calibration of military IR test equipment is an approach being explored to avoid perceived shortcomings of traditional thermometric calibration. This issue has profound impact on the testing of military systems: the lack of internally consistent calibration architecture can cost military customers millions of dollars in increased maintenance and spares costs due to test result inconsistencies. An example is presented to show that the lack of a standard spectral response definition in this region, and the difficulty in making such a definition, make the radiometric calibration approach seem questionable for the foreseeable future. Calibration errors of more than 7% (not even a worst-case scenario) can result. The best approach to assuring test accuracy and calibration consistency is to employ thermometric calibration in conjunction with intelligent test system design: high, flat spectral transmittance of the test system and high emissivity targets and sources. These are achievable today with proper application of existing materials and coatings.