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

From: Alan Dechert <alan_at_openvotingconsortium_dot_org>
Date: Sat May 01 2004 - 13:47:06 CDT

David,

> On Apr 30, 2004, at 9:23 PM, Alan Dechert wrote:
> > I'm not sure of these calculations and I'm not sure compression could
> > not be
> > used effectively.
>
> Compression as such is really just not workable. It just can't work to
> have the barcode be of indeterminate size (and possibly longer than
> usable). ....
>
Maybe the problem is semantical.

> However, rather than -compression- we can use more optimal
> encodings of contests, thereby obtaining theoretical best sizes. It is
> not difficult to create an optimal encoding for each contest type.
>
Perhaps "optimal encoding" is what I am thinking of as a form of data
compression.

Here's something I pointed out when we had this discussion last AUG:

     The possibilities for the first 7 bits are:
     1000000
     0100000
     0010000
     0001000
     0000100
     0000010
     0000001
     0000000

Currently, we indicate each bit one-by-one so we use 7 bits. However, there
are only 8 possible patterns for these 7 bits. These 8 patterns could be
represented by 3 bits if you had a way to map these patterns to 000 001 010
011 100 101 110 111.

I figured that using this "compression" method, the digits or symbols needed
on the barcode could be about half. Instead of 3 inches, the barcode could
have been 1.5 inches. After testing with the scanner, we decided it wasn't
necessary so I dropped the idea.

Arthur mentioned a scheme he had devised that would be even more efficient
at "compressing" the data.

Alan D.
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Received on Mon May 31 23:17:01 2004

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