The spectral response of cameras is often reported as the product of the individual responses of the elements in the optical path, the lens element coatings, filter (if available), FPA window and coating, and detector elements. This data is often incomplete or inaccurate as vendors will often provide limited spectral data or the data is measured under conditions different than those in the camera system (i.e., normal incidence assumption). We have designed and built an instrument for the measurement of the normalized spectral response of camera systems in the thermal bands (MWIR [3um-6um] and LWIR [8um – 12um]). The design utilizes a series of narrowband filters, a cavity blackbody and other components for the conditioning of the stimuli to the camera. The normalized camera spectral response is obtained by comparing the camera response to each narrowband filter against a reference measurement. In this paper we discuss the modeling and analysis in support of the design, show the final design and some preliminary measurements.
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