Abstract

Any linear shift-invariant imaging system can be completely described by its point spread function (PSF) or its optical transfer function (OTF). If the system has rotational symmetry, the full 2-D PSF or OTF is not needed, only a radial line through either the PSF or the OTF. Alternatively the line spread function (LSF), the image of an infinite line, may be used as the 1-D description. There are, however, important imaging systems that are not well described by the LSF. One reason for failure of the LSF description is that the system may have a relatively small region of isoplanaticity so that a long input line is not permitted. We present here an alternative 1-D description of the system which we term the finite-length line spread function (FLSF). The FLSF is the image of a finite-length line. The relation of the FLSF to the PSF and the OTF is conveniently described by a new integral transform.

© 1987 Optical Society of America