After a report on the composition of two incoherent rectilinear vibrations with perpendicular polarizations, we suggest in this paper a method of extraction of the difference between two images in incoherent and polarized light. The images, perpendicularly polarized, are simultaneously recorded on a silver chloride emulsion H where an optical anisotropy is induced only in the areas where the incident intensity distributions are not identical. After exposure, H, observed between crossed polarizers, displays the difference between the two original images in its image plane. In addition, it is shown that the sign of this difference is retrieved by means of the dichroism of the plate. © 1979.
