Handy method to calibrate division-of-amplitude polarimeters for the first three Stokes parameters.

Abstract

This paper presents a complete and original calibration framework for the three-CCD polarimetric cameras. These Division-of-Amplitude imaging polarimeters provide polarization images in real-time and open new applications in robotics. In order to fully exploit properties from polarization images, the sensor has to be calibrated leading sometimes to a tedious task that has to be undertaken with specific optical devices in a controlled environment. The proposed framework relies only on the use of a tablet and enables both to calibrate the geometric and the polarization settings of the camera. After rotating freely by hand the tablet in front of the camera, the system is automatically calibrated providing both the well-known geometric calibration matrix as well as the polarization calibration matrix. The last one is derived from the estimation of the orientation of the three polarizers, and the estimation of their relative values of degree of polarization and average transmittance.