Polarization-aided image contrast enhancement with rotating polarization element and control software

Abstract

Polarization-aided image contrast enhancement is disclosed. A rotatable polarizing element (e.g., a linear polarizer, waveplate and static polarization analyzer, etc.) may be inserted in front of an imaging camera (e.g., between the optics and camera of a telescope) to suppress a significant amount of polarized background sky brightness due to sunlight scattered by aerosols and gas particles in the sky and enhance imaging contrast of the field. This may be accomplished by installing a linear polarizer into a motorized rotation stage. As the polarizer rotates in the stage, transmitted sky brightness will vary sinusoidally with polarizer orientation. At any point in the sky and at any time, there will exist a polarizer orientation that minimizes transmitted sky intensity and maximizes contrast in the image.