Imaging through the atmosphere: Practical instrumentation-based theory and verification of aerosol modulation transfer function: Reply to comment Academic Article uri icon


  • New exact numerical calculations as well as exact calculations in J. Opt. Soc. Am. A10, 172 ( 1993) indicate that the approximations in the Comment in J. Opt. Soc. Am. A11, 1175 ( 1994) are based on faulty perceptions of basic scattering phenomena and on a misreading of our paper. The Comment does not sufficiently consider effects of instrumentation. Whereas our model refers to the aerosol modulation transfer function (MTF) in the image plane, the values of maximum angles for scattered (θS) and unscattered (θ0) light used in the Comment refer to the optics plane. The Comment does not consider the fact that dynamic range limits (θS) in the image, whereas limited spatial-frequency bandwidth broadens θ0 in the image, each by orders of magnitude. Therefore the Comment’s conclusion contradicts experimental results obtained by numerous researchers. The Comment’s conclusion that aerosol MTF is insignificant is based on that author’s own experiments, in which clear weather and haze atmospheric MTF (composed of turbulence and aerosol MTF’s) could not be measured, the reason being insufficient equipment resolution, rather than insignificant turbulence or aerosol MTF. Furthermore, the claim in our original paper that aerosol MTF is extremely significant has since been supported by many different types of experiments that included short and long exposures, thermal imaging, and image restoration based on atmospheric MTF, including a highly significant practical, uniquely shaped, aerosol MTF.

publication date

  • January 1, 1995