Barcode module for EasyFile
Bar Code Symbologies
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 www.amazon.com
by Roger C. Palmer It may not be in your local bookstore, but it is available
on the Internet.
Bar Code Pros and Cons
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.
2D Bar Codes
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.
Using Bar Codes
Bar codes are used in document scanning in three common ways:
- Pre-printed on the document as a document ID
- Pre-printed on a separator pages to indicate that a document is ending and
a new document is beginning
- Printed on labels (either pre-printed or printed on demand) and affixed to
documents with unique values.
Each approach addresses different issues. Ask your vendor or consultant to
discuss which the best is for you.
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