When designing camera systems, (for instance, in a cell phone), one important source of image degradation can come from stray light. This can result in ghost images caused by unwanted reflections off internal lens surfaces, or by out of field light being scattered from spacers or other surfaces in the optical system. In this paper, we demonstrate a method for characterizing the glare spread function (GSF) of an optical system using ray trace simulations. The GSFs can then be interpolated at angles and wavelengths that were not traced. Interpolated GSFs are applied to in-field image points as well as out of field points and then combined with the primary imaging path image. The result accurately predicts the detector illuminance.
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