Reconstructing Polarisation Components from Unpolarised Images

In this paper, we develop a method for reconstruct- ing the polarisation components from unpolarised imagery. Our approach rests on a model of polarisation which accounts for reflection from rough surfaces illuminated at moderate and large angles of incidence. Departing from the microfacet structure of rough surfaces, we relate the maximal and minimal polarimetric intensities to the diffuse and specular components of an un-polarised image via the Fresnel reflection theory. This allows us to reconstruct the polarimetric components from a single unpolarised image. Thus, the model presented here provides a link between the microfacet structure and polarisation of light upon reflection from rough surfaces. We evaluate the accuracy of the reconstructed polarisation components and illustrate the utility of the method for the simulation of a polarising filter on real-world images.