Stray light is the part of an image that is formed by misdirected light. I.e. an ideal optic would map a point of the scene onto a point of the image. With real optics however, some parts of the light get misdirected. This is due to effects like scattering at edges, Fresnel reflections at optical surfaces, scattering at parts of the housing, scattering from dust and imperfections – on and inside of the lenses – and further reasons. These effects lead to errors in colour-measurements using spectral radiometers and other systems like scanners. Stray light is further limiting the dynamic range that can be achieved with High-Dynamic-Range-Technologies (HDR) and can lead to the rejection of cameras due to quality considerations. Therefore it is of interest, to measure, quantify and correct these effects. Our work aims at measuring the stray light point spread function (stray light PSF) of a system which is composed of a lens and an imaging sensor. In this paper we present a framework for the evaluation of PSF-models which can be used for the correction of straylight. We investigate if and how our evaluation framework can point out errors of these models and how these errors influence straylight correction.

Date Published: 27 February 2015
PDF: 13 pages
Proc. SPIE 9404, Digital Photography XI, 940406 (27 February 2015); doi: 10.1117/12.2078333

Published in SPIE Proceedings Vol. 9404:
Digital Photography XI
Nitin Sampat; Radka Tezaur; Dietmar Wüller, Editor(s)