Real-time objects recognition by photoanisotropic copies.

The method of object recognition is described by the example of objects of amplitude transparent type. The method is to obtain a photoanisotropic copy of object images on polarization-sensitive material. At consequent illumination of the photoanisotropic copy with a parallel circularly polarized beam of nonactinic light, the transmitted light becomes elliptically polarized. It is shown that the characteristics of the summary polarization ellipse in the Fraunhofer diffraction region uniquely identify the given object. The real-time determination of the characteristics of the summary polarization ellipse is made by means of diffraction gratings of anisotropic profile and by comparison of these characteristics with etalon from the database.