Robust calibration method for polarization cameras integrated with chromatic retarders

Abstract

Polarization cameras provide a compact and efficient solution for real-time polarization imaging but suffer from chromatic calibration errors when used in combination with wavelength-dependent optical components such as linear retarders. In this work, we introduce an analytical calibration method specifically designed for polarization cameras integrating chromatic retarders, which can be used both in monochromatic and color sensors. This method algebraically accounts for spectral averaging and depolarization effects arising from wavelength-dependent retardance, enabling robust and accurate polarization calibration across different spectral channels. The approach is experimentally validated using a commercial color polarization camera (FLIR Blackfly S) with integrated RGB Bayer filters and micro-polarizers, along with broadband illumination sources. Experimental results demonstrate that the effective spectral parameters, such as the effective wavelength and spectral bandwidth obtained by our calibration method, are close to theoretical predictions.