Polarization Diversity Active Imaging: Mueller Matrix Imaging Polarimetry of Spheres and Cones Estimation of the Refractive Index from the Polarization Signatures

A previous study presented interesting data indicating the ability of the Polarization Diversity Active Imaging techniques PDAI to measure polarization signatures of objects of simple shape conical and spherical objects. Polarimetric signatures of such objects are obtained by applying a powerful decomposition technique, previously developed under earlier AFOSR contract. A complete description of the object in then obtained. Such decomposition can be used for detection, discrimination and classification of targets. This second phase has extended the study of the dynamic behavior of one of the previous targets cone used as a re-entry vehicle mode. By then rotating that sample target to make polarization movie, the evolution of the decomposed polarization signature can then the fully examined. The analysis performed for each position finally provides the dynamic behaviors of the target depending on either its orientation or the position of the detection system. The second goal of this phase was the development of a method for estimating the refractive index of a target from its Mueller matrix image. Our investigations show that the refractive index can be estimated either by using data resulting from the polar decomposition method or from the Mueller matrix image of the object after different steps of data processing. Such parameter is essential in order to progress in the understanding of these polarized highmaterial interactions.