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This U of A Invention Is Used by the Post Office Every Day

This U of A Invention Is Used by the Post Office Every Day

A device invented by U of A engineers can recognize these barcodes, no matter where they appear on the envelope.

The wide area bar code reader allows the U.S. Postal Service to process mail faster and more efficiently than previous methods. The reader was developed by University of Arkansas engineering professors J.E. Bass, Randy Brown and Dwight Mix in 1991.

Mix explained that Bass brought the idea to the university, proposing that the U of A take part in a large research endeavor sponsored by the Postal Service. Universities and research labs across the country were working on the same problem: the Postal Service needed a better way to find bar codes on envelopes.

When you send a piece of mail, the address is scanned and turned into a bar code that is printed on the envelope. These days, a device called an optical character reader interprets the address, but in 1989, when the project started, the addresses were read and coded by employees. When mail reaches the post office near its destination, the barcode is read and the mail is sorted according to the information it contains.

The bar code reader in use at the time had to be lined up directly over the bar code in order to read it. This meant every bar code had to appear exactly the same distance from the edges of the envelope, and this proved challenging to achieve. So the Postal Service decided they needed a bar code reader that could scan the entire envelope first and identify the bar code, no matter where it was located. And the device had to work fast, scanning nine envelopes per second.

To Mix, who specialized in pattern recognition, the solution was simple. He knew that all post office bar codes had a consistent horizontal pattern of lines. The researchers used a technique called correlation, programming the device to scan the envelope until it located this distinct pattern.

After two years of work, all of the research centers gathered in Washington, D.C., to demonstrate their prototypes. The U of A’s device was 100 times faster than the Postal Service had requested, and many more times faster than the closest competitor, which used complicated artificial intelligence techniques and took three minutes to scan one envelope.

Today, every post office uses the wide area bar code reader developed at the U of A.

About The Author

Camilla Shumaker is the director of science and research communications. She writes about physics, chemistry, political science and other topics. Camilla can be reached at or (479) 575-7422.

University Relations Science and Research Team

University Relations Science and Research Team

Matt McGowan
science and research writer

Robert Whitby
science and research writer

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