Dual Radiance Standards Can Minimise Calibration Uncertainty in the SWIR Region

The benefit of using integrating spheres to generate a highly uniform radiance or luminance sources for the calibration of sensors and cameras has been well documented and is established practice by many calibration laboratories and instrument manufacturers. However, the spectral radiance in the absorption features of the SWIR region of an integrating sphere source are generally not characterised with sufficient detail for hyper-spectral calibration across these features resulting in large uncertainties. In addition the spectral width and depth of these features is dependent on the specification of the national or traceable laboratory’s instrumentation and may differ significantly from the hyperspectral camera. Generating a radiance source form an irradiance standard and reflectance panel produces has a more predictable spectrum with shallower features in the SWIR region. By combining the two calibration techniques the uncertainty in SWIR region can be reduced whilst maintaining the uniformity attributes of an integrating spheres source.