Line spread function formulation proposed by W. H. Steel: a revision.
A revised formulation of the image light distribution of an incoherent line source proposed by Steel [Rev. Opt. 31, 334-340 (1952)] is presented. Analytical and numerical results based on this new representation are given. We explicitly show that a major error in Steel's final expression generates singularities, thereby preventing convenient numerical computation.
Edge image processing: An analysis of modified heaviside functions as degraded edge generators
Our main goal in this analysis is to find the best representation for degraded or soft edges and the resultant image intensity distributions with these objects. We reproduce analitically real edges. In order to predict the degradation parameters, we analize their associated LSF's and MTF's. All objects are defined as modified Heaviside functions',i.e., Heaviside degraded with an exponential function and a modified sigmoid. The entire solution for the image intensity distribution is given in terms of a convolution of the degraded edge and the Line Spread Function (LSF). The LSF is given in terms of a series expansion of Bessel functions2 of order 2n, J2 (x), as an optimized representation for implementing systematic computational procedures.
Determination of the Radial Distribution of Brightness in a Cylindrical Luminous Medium with Self-Absorption
The two-path method (utilizing a mirror) is shown to provide sufficient information to solve for the true radial brightness distribution of a luminous medium in the presence of self-absorption. In the case where self-absorption is not large, an approximate solution to the problem is shown to be no more difficult than a solution for the “optically thin” approximation.