Method of eliminating errors in images derived from patterns which consist of periodically arranged individual images

Claim 1

A method of correcting errors in imperfect periodic two-dimensional patterns comprising: optically forming a composite Fraunhofer diffraction image of the periodic two-dimensional pattern, whereby a plurality of groups of individual diffraction images are formed, each group forming a ring about a single central individual diffraction image, each ring corresponding to a single diffraction order of the pattern, and passing only a ring-shaped plurality of the individual diffraction images from one of the rings representing a single diffraction order through an optical filter, forming an inverse Fraunhofer diffraction image of the filtered individual diffraction images, and recording said inverse diffraction image on an imperfectly planar surface.

Claim 2

A method of correcting errors in imperfect periodic two-dimensional patterns comprising: optically forming a composite Fraunhofer diffraction image of the periodic two-dimensional pattern, whereby a plurality of groups of individual diffraction images are formed, each group forming a ring about a single central individual diffraction image, each ring corresponding to a single diffraction order of the pattern, and passing only a ring-shaped plurality of the individual diffraction images from one of the rings representing a single diffraction order through an optical filter, forming an inverse Fraunhofer diffraction image of the filtered individual diffraction images, and recording said inverse diffraction image on an imperfectly planar surface.