Although difficult for humans to read, bar codes (also spelled barcodes) are great for computer literacy. Your average PC can read a long bar code in a fraction of a second with almost no chance of a mistake.
There are a number of different types of bar codes, called "symbologies." The most popular ones, like Code 39, Interleaved 2 of 5, or Postnet are simple one dimensional symbologies, meaning they consist just of lines. There are also two dimensional bar codes which can encode a great deal of information. The "bible" of bar code recognition is The Bar Code Book by Roger C. Palmer. It may not be in your local bookstore, but it is available on the Internet.
Although not easily read by people, bar codes are a very sure way of passing information from a piece of paper into your computer. They are read fast and with amazing accuracy. Of course, bar codes have their drawbacks. For example, if a bar code is not read by the recognition engine, then what to do? It is important to always put a human readable version of the value on the same page as the bar code itself. Sometimes you can even use OCR as an automatic fall back if a bar code is not read.
Bar codes allow you to put some key information on a page, and read that information with high reliability. Standard one-dimensional bar codes, however, can hold only a very limited amount of information. Depending on the size of the code, and the symbology, you may only have room for one to two dozen characters. What if you want to get much more information into a bar code? Two dimensional (2D) bar codes can encode hundreds of characters in a very small amount of space. PDF 417 is the most popular 2D bar code symbology. The disadvantage of using PDF 417 or other 2D bar codes is that normally there is no room to also print the human readable value that is encoded. That means that a failure to read a PDF 417 code will result in the inability to lift data from the document. That's why PDF 417 and other 2D bar codes (such as DataMatrix) include redundancy in their values.
Bar codes are used in document scanning in three common ways:
Each approach addresses different issues. Ask your vendor or consultant to discuss which is the best for you.
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