Polarimetric image processing: an important new tool for forensic science

The author describes a powerful visual probing technique which could be of benefit to forensic scientists. 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. 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 provide an adequate perspective on the capability of an imaging polarimeter, and how polarimetry could become an important technique for forensic science, the relevant theoretical basis for the processing of polarimetric images is presented