An OCR machine printed problem is selected as an example of a large class pattern recognition problem. We consider discrimination of alpha and numeric fields, recognition of all numbers, recognition of key words (street suffixes, personal titles), state/city/street names, etc. These operations are performed on destination address blocks (DABs) in the face of numerous variations in the type face (laser writer, dot matrix, typewriter, etc.), font, data drop out (due to printing errors), point size, +/- 5 degree(s) rotations, etc. An optical correlator with banks of distortion invariant hierarchical/inference filters appears to be an ideal adjunct to other OCR techniques (AI, parsing, context, use of lexicons, etc.).