Active spectro-polarimetric imaging: signature modeling, imaging demonstrator and target detection

¹ Thales Research & Technology - France, RD 128, 91767 Palaiseau Cedex, France
² Laboratoire Charles Fabry de l'Institut d'Optique, CNRS, Univ Paris-Sud, Campus Polytechnique, RD 128, 91127 Palaiseau, France
³ Physics and Image Processing Group/Fresnel Institute, Domaine Universitaire de Saint-Jérôme, 13397 Marseille Cedex 20, France
⁴ Thales Oprtonics Thales Optronique SA, rue Guynemer, BP 55, 78283 Guyancourt Cedex, France

Corresponding author: mehdi.alouini@thalesgroup.com

Received: 16 October 2007
Revised: 11 January 2008
Accepted: 15 January 2008
Published online: 28 March 2008

Abstract

We report on the synthesis of our work on the analysis of active spectro-polarimetric imaging concept of real-world scenes. These synthesis extend from the investigation of depolarization mechanisms up to image analysis and processing. We show in particular that depolarization effects are wavelength dependent and strongly correlated with light absorption of materials. Multi-wavelength images of degree of polarization are recorded and analyzed, evidencing that the polarimetric image must be interpreted in conjunction with its counterpart intensity image in order to extract, the most relevant information from the scene. For real field operation, the noise characteristics of polarimetric images are also investigated under coherent laser illumination. The potential increase of target detection performance brought by properly processing the active polarimetric image is illustrated on a very low contrast scene.