Asymptotic behavior of the spatial frequency response of an optical system with defocus and spherical aberration.
Asymptotic expressions are derived for the two-dimensional incoherent optical transfer function (OTF) of an optical system with defocus and spherical aberration. The two-dimensional stationary phase method is used to evaluate the aberrated OTF at large and moderately large defocus and spherical aberration. For small aberrations, the OTF is approximated by a power series in the aberration coefficients. An accurate approximation (in elementary functions) to the OTF is obtained for a defocused optical system with a circular pupil. We experimentally demonstrate the validity of the OTF approximations in sharp-focus image restoration from two defocused images. A digital focusing method is presented.
A.V. Schendelplein 137, 2624CV Delft, The Netherlands. A.N.Simonov@gmail.com
Aleksey N
AN
Simonov
Michiel C
MC
Rombach