Aerosol MTF revisited

Abstract

Different views of the significance of aerosol MTF have been reported. For example, one recent paper [OE, 52(4)/2013, pp. 046201] claims that the aerosol MTF "contrast reduction is approximately independent of spatial frequency, and image blur is practically negligible". On the other hand, another recent paper [JOSA A, 11/2013[JOSA A, 11/ , pp. 2244[JOSA A, 11/ -2252 claims that aerosols "can have a non-negligible effect on the atmospheric point spread function". We present clear experimental evidence of common significant aerosol blur and evidence that aerosol contrast reduction can be extremely significant. In the IR, it is more appropriate to refer to such phenomena as aerosol-absorption MTF. The role of imaging system instrumentation on such MTF is addressed too.

Passive adaptive imaging through turbulence

“…This behavior is similar to that reported by Kopeika with regard to a supposed aerosol MTF (e.g., Kopeika et al, 2014), but this has been discounted numerous times. For example, Eismann and LeMaster (2013) developed an aerosol MTF but report it has negligible image blur effects and is nearly independent of spatial frequency.…”

Measuring resolution degradation of long-wavelength infrared imagery in fog

“…The resolution loss caused by scattering in aerosols and fog has been well-studied for visible light. 1,6,7,13,[15][16][17][18][19][20][21][22][23] Some of the studies determined the effect of image blurring was negligible. 13,21,22 However, other studies demonstrated that image blurring significantly decreased image quality.…”

“…13,21,22 However, other studies demonstrated that image blurring significantly decreased image quality. 7,[17][18][19][20]23 Sadot et al 24 showed that scattering from aerosols significantly affected LWIR image quality in clear conditions. The previous measurements [10][11][12]14 of LWIR imaging performance through fog did not account for the resolution degradation cause by blurring.…”