Re: How big could a bar code be if a bar code could be big?

From: Alan Dechert <alan_at_openvotingconsortium_dot_org>
Date: Fri Apr 30 2004 - 16:24:12 CDT

>
> #bits ~= 3.32192809488736234789*#digits.
>
> (That magic number is ln(10)/ln(2), or log2(10).)
>
> For example:
>
> 36 digits -> ~120 bits
> 50 digits -> ~166 bits
>
Thanks, Steve. So, I stick with my estimate of 150 bits as a practical
limit for el cheapo 1-d scanner without using compression. This is a bit
subjective for sure. There is some skill requirement as the length
increases. Even with a laser scanner, you have to get the line to
end-to-end on the barcode--a six inch barcode would require the operator to
hold it pretty straight. With a wand scanner, I've found 4-5 inch barcodes
to be not too bad.

I would like to investigate using compression. Back in August, Arthur was
talking about self-delimiting variable-length codes.
http://gnosis.python-hosting.com/voting-project/August.2003/0237.html

Alan D.
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Received on Fri Apr 30 23:17:28 2004

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