Polarimetric image processing: an important new tool for remote sensing

Whenever electromagnetic radiation is reflected from a surface, it becomes polarised to a degree, dependent upon surface structure, texture and angle of incidence. If the polarisation information from the reflected radiation is extracted from conventional intensity information by an imaging polarimeter it is possible to reveal detail about the surface that cannot be obtained by any other imaging technique. Hence, polarimetric images provide the means of observing objects and phenomena that are invisible to conventional imaging systems. An imaging polarimeter produces images representing the spatial variation in polarisation over the scene, which can be related to true texture, surface structure and material type. To date, polarimetric imagery has been completely neglected as a powerful, nonintrusive visual probing tool. Therefore, to provide an adequate perspective on the remote sensing capability of an imaging polarimeter, and how polarimetry could become an important technique for visual probing, the relevant theoretical basis for the processing of polarimetric images is presented