Statistical processing of polarization diversity images

Abstract

Polarization diversity active imaging techniques have the appealing feature of revealing contrasts that do not appear in conventional intensity images. However, the intensity images provided by the system are in general not useful due to their perturbation by atmospheric turbulence and spatial inhomogeneity of laser sources. It is thus preferable to process only the image that represents the degree of polarization (DOP) of the reflected light. In this chapter, the analysis will be devoted to the particular case of purely depolarizing materials which are defined by their property of having diagonal coherency matrices whatever the incident state of polarization. We discuss some statistical results of the Orthogonal State Contrast Image (OSCI) which is nothing but the degree of polarization when the coherency matrix is diagonal. We also analyze some estimation properties useful for image processing. These results are illustrated on target detection and segmentation processing tasks. We demonstrate that simple but still very efficient algorithms can be developed.