Modern(-ish) scanners have an option to perform OCR on scanned
documents. I've seen such PDF files that have a big image of the scanned
documents as a back-ground, with lots of transparent text on top. That
allows for the user to copy-paste text (OCR-ed) from such scanned documents.
I vaguely remember a scanner that used to split the page in
rectangles with less-than-one-page images if there was much white space
on the page.
On another note: there are many PDFs that contain pages with just one
big image per page. Presentations occasionally...
To the original poster 'achilles': there is no reliable way to detect
whether PDF file is a result of a document scan process, or has been
crafted. However Ulf Dittmer's suggestion to look for pages with just a
big image per page is (probably) the best option.
На 20.11.24 г. в 12:49 ч., Ulf Dittmer написа:
I'm not quite sure what you mean by "scanned pdf", but if each page
basically consists of one image, and no text, that might be a strong
indication.
On Wed, 20 Nov 2024, 11:05 achilles, <1743702...@qq.com.invalid> wrote:
hi:
How can i judge a PDF is a Scanned PDF use pdfbox?
i don't find a api to judge a PDF is a Scanned PDF without any
text, i need you help, thank you!
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