Polarization calibration assessment for a broadband imaging polarimeter based on a division of aperture architecture

Abstract

This article intends to provide all the experimental insights and analyze the best polarimetric calibration method for a division of aperture polarimetric imager considering the different implications it has on the experimental set-up and its performance. Polarimetric cameras require careful calibration for the correct measurement of polarization information. The calibration methods are introduced, intermediate results are presented, and the ability of the set-up to estimate Stokes vectors and Mueller matrices of the samples in passive and active imaging modes is evaluated. Polarization information recovery achieves accuracy errors below the 10% for all polarization modes when the Data Reduction Matrix or the Eigenvalue Calibration Method are used. Such performance, however, degrades significantly when using the Polarizer Calibration Method. To the best of our knowledge, this is the first time such a detailed comparison of calibration methods is presented in the literature, and it is also the first time the Polarizer Calibration Method is applied to a division of aperture polarimeter.

Optimal snapshot full-Stokes imaging polarimeter in the visible band based on division-of-aperture

“…Several methods exist in the literature and some of them are specially designed for the polarimeter under development. A comparison 12 was performed regarding the general methods, to find the most suitable method for a DoAP imaging polarimeter. The results concluded that the Data Reduction Matrix method 13,14 (DRM) performs better for a full-Stokes polarimeter working in the VIS range.…”

“…A solution to this issue 13 is to use SVD to recover the pseudoinverse of 𝑰𝑰. The procedure and the experimental set-up for the polarimetric calibration are explained in Peña-Gutiérrez et al 12 , where optimal RPS are employed to reduce the error in acquisition.…”

“…This LP is rotated between 0º and 180º in steps of 10º and their output polarization state is recovered by our system. The resulting calibration matrix 𝑾𝑾 from DRM and the employed RPS are explained in Peña-Gutiérrez et al 12 in detail.…”

Optimal Mueller matrix imaging polarimeter in the visible band based on division-of-aperture

“…This analyser is comprised of elliptical four polarization states, one for each optical path resulting from the division at the aperture. Each of these RPS is generated by a retarder and a horizontal linear polarizer [9][10] , which is common for all the retarders.…”

“…The radiometric calibration accounts for the variance of the behaviour of the pixels in the sensor. Therefore, we characterise the sensor by measuring the dark noise response when no excitation of the pixels is present and the flat pattern which shows the behaviour of each pixel when the surface is homogeneously illuminated 10 . This pattern can retrieve the differences between pixels at the centre or on the sides and get rid of dead and saturated pixels.…”