Radiant power from the images of adjacent point sources will spill over into each other even though their separation is greater than the system resolution element. This spillover or system optical crosstalk can be troublesome if a point source of interest is in the vicinity of a much brighter point source. A method is presented for computation of the constituent of system optical crosstalk due to optical surface scatter. This analysis provides the scatter function at the image based on the scatter function for each surface and the surface position along the optical path.
Silas H. Brewer, Silas H. Brewer,
"System Optical Cross Talk", Proc. SPIE 0294, New Methods for Optical, Quasi-Optical, Acoustic, and Electromagnetic Synthesis, (26 February 1982); doi: 10.1117/12.932353; https://doi.org/10.1117/12.932353