Structured from/within unstructured documents

["Stephen Green" <stephengreenubl@gmail.com>]

What methods are there, these days, for extracting structured data from
unstructured documents (such as PDF)?

I'm aware it is quite straightforward to extract data from semi-structured
documents such as spreadsheets (as previous XML-Dev discussions have
shown, such as via ODF with XSLT and macros/Ant/Ant Contrib, etc).

As yet, the only way I'm aware of for doing the same from PDF would be to
print out to paper and use OCR (sounds a little ridiculous) or maybe to
convert PDF, etc to some XML-based or other text-based print/archive
file somehow and go from there (perhaps with something akin to a screen-
scraper?).

Is this all there is?

Plus how does one then convert the data as, say XML into some XML
or equivalent document and embed that in, say, the PDF or equivalent
unstructured document file (for later extraction, say)?
I'd very much appreciate any light on this. Thank you. I'm interested not
so much in metadata but actual data or full structured equivalents of the
unstructured documents rather than just enough data to create an index.

E.g what about patient records held in PDF and in XML formats and how
to turn the first into the latter and/or embed the latter in the first.

Best regards

-- 
Stephen Green

Partner
SystML, http://www.systml.co.uk
Tel: +44 (0) 117 9541606

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