Re: Scanner, write-ins, printer (was Re: Barcode -- printed ballot)

From: Jan Karrman <jan_at_it_dot_uu_dot_se>
Date: Sat Sep 13 2003 - 14:33:37 CDT

On Sat, 13 Sep 2003, Edward Cherlin wrote:

> Accuracy is ensured by error-correcting coding, that is by adding
> redundancy in a controlled manner, not by removing all possible
> redundancy. Error correction must be part of the bar code
> standard we adopt.

The only one-dimensional bar code I believe can be used for the
demo is Code128. This uses a checksum character that gives a
certain level of guarantee that the bar code is correctly scanned.
This should be good enough for the demo. I have also made a GPL
font of Code128 that probably will be used there. Code128 has
the advantage that cheap bar code readers has support for it.

For the production system a two-dimensional bar code, such as
PDF417, may be used. This has a much more sophisticated level
of error correction, see for example:

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Received on Tue Sep 30 23:17:04 2003

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