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

From: Reg. Charney <charney_at_charneyday_dot_com>
Date: Sat May 01 2004 - 16:24:45 CDT

I know that I am joining this discussion late, but what guarantees does
the voter have that the contents of their ballot are accurately
represented in the bar code?

Reg.

Alan Dechert wrote:

>>#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 Mon May 31 23:17:01 2004

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