Postal address reading in real time

Abstract

In 1994, the U.S. Postal Service (USPS) delivered 177 billion pieces of mail to 125 million delivery addresses. To assist in processing this large volume of mail, USPS and the Center for Document Analysis and Recognition (CEDAR) have been exploring automation methods for processing letter mail with handwritten addresses. The CEDAR system for locating and reading destination address blocks on letter mail pieces operates at real-time rates. The system architecture uses a variety of pipelining and multiprocessor techniques to achieve the required processing speed and minimize latency. Image processing operations are performed using specialized hardware operating at 103 ns/pixel. This hardware includes CCITT Group 3 (FAX) decompression, image enhancement, and conversion of the image representation from pixel-based representation to symbolic representation. This symbolic representation of the image can be processed in real time using software running on general-purpose processors. This software performs the address block location (ABL), handwritten address interpretation (HWAI), and data base querying needed to determine the delivery point of the mail piece. The current system can correctly locate and produce a five-digit ZIP code with an accuracy of 66% on a test set of 1566 handwritten mail pieces. A unique delivery point (e.g., ZIP + 4 code) can be determined on these same mail pieces 26% of the time. © 1996 John Wiley & Sons, Inc.