Effect of spectral emissivity on single broadband MWIR image simulation
Abstract
The question of whether it is always appropriate to assume in the generation of synthetic, single broadband midwave infrared (MWIR) imagery that the emissivities of scenery objects are constants with respect to wavelength is addressed. In the radiometric measurement equation, the detector signal due to the image plane irradiance within a finite waveband is proportional to the integral of the detector spectral responsivity times the scene radiance, and the scene radiance is the directional spectral emissivity of the scene times the spectral radiance of a blackbody at the same temperature. Using the spectral emissivity data of a set of commonly encountered scenery materials and different temperatures, single broadband MWIR image signals from idealized thermal and InSb-type photon detectors were computed using the measurement equation with spectral emissivity and detector responsivity and with several emissivity and detector responsivity approximations for comparison. The results show a strong correlation between the relative variation, or fractional standard deviation, of the average MWIR emissivity and the error in the emissivity/responsivity approximation results relative to the spectral emissivity/responsivity results.
Publication Title
Proceedings of SPIE - The International Society for Optical Engineering
Recommended Citation
Hodgkin, V., & Jacobs, E. (2002). Effect of spectral emissivity on single broadband MWIR image simulation. Proceedings of SPIE - The International Society for Optical Engineering, 222-234. https://doi.org/10.1117/12.478809
