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UB-Mannheim / zotero-ocr

Zotero Plugin for OCR
GNU Affero General Public License v3.0
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Running OCR on embedded images of PDF using Poppler pdfimages or ImageMapping instead of whole pdf pages converted to png? #84

Open T-Dane opened 3 weeks ago

T-Dane commented 3 weeks ago

Requesting a version of PDF OCR that only runs tesseract OCR on embedded images in PDF instead of capturing the whole page of the PDF.

A lot of my professors use powerpoints converted to PDF, the text is already text, while the screen-grabs they use lack this and could benefit from OCR.

I believe this could save time for others as well as not all PDF documents are purely images and often a combination.

aborel commented 3 weeks ago

Interesting idea, but inserting the OCRed text back into the existing text layer for hybrid pages might be challenging. I'm not familiar with ImageMapping, can you provide a link?

T-Dane commented 2 weeks ago

I completely trust it would be challenging, but it would make for an AMAZING feature! This: https://poppler.freedesktop.org/api/glib/poppler-Poppler-Page.html#PopplerImageMapping-struct

Or maybe this: https://world.pages.gitlab.gnome.org/Rust/poppler-rs/stable/0.24/docs/poppler/struct.ImageMapping.html

aborel commented 2 weeks ago

Thanks. We're currently looking into reducing the dependencies on external programs, so I'm not sure we'll use your suggestion, but we'll keep this in mind.