Multiclass optical correlation filters for alphanumeric field recognition

We consider the use of new distortion-invariant optical correlation filters for machine-printed OCR. Our work is unique in its treatment of a large set of different fonts, printer types, plus rotations and scale (point size) variations, and various practical issues such as printing artifacts and background noise. We detail their use in the locations and recognition of alphanumeric fluids (digits) in destination address blocks (DABs).