OCR for punchcards?

From: Ethan Dicks <ethan_dicks_at_yahoo.com>
Date: Fri Jun 22 17:30:38 2001

--- Jim Strickland <jim_at_calico.litterbox.com> wrote:
> It just occurred to me that it should be possible to write OCR software
> to read punchcards on your scanner. Not that I have any punchcards
> mind you, more of an intellectual exercise, but has anyone written
> such a thing?

I started to... I stuck the punch card in the sleeve my sheet-feed Brother
scanner comes with for torn pages, and backed it with a piece of colored
paper for contrast through the holes. I scanned it at 200 dpi, then
converted the TIFF to GIF and was using Tom Boutell's GD library to slurp
the GIF file in (an old, pre-PNG version of GD). I got as far as scaling
the scan and doing some edge detection. Oh, BTW, I scanned the *back* of
the punch card to avoid having to figure out what was holes and what was
printed on the card.

I got distracted by other projects and never went back to it because I don't
have any punch cards with real data to scan, only some that came with a
Computer Science correspondence course that I picked up at a local thrift
store for $0.75.


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Received on Fri Jun 22 2001 - 17:30:38 BST

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