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Plugins / Reading & PDFs

PDF OCR Helper

by Philippyang21 · github.com/Philippyang21/zotero-pdf-helper

Adds an invisible text layer to scanned PDFs using PaddleOCR and tidies highlighted quotations.

PDF OCR Helper has Atlas grade B (use with care) because it launches programs on your computer. It works with Zotero 7–10. Last checked 6 Nov 2026.

Reading & PDFsImport & metadata
View source
Downloads a .xpi file (2.3 MB). In Zotero, open Tools → Plugins and install it from the file.
In useAn estimate of how many copies of Zotero have it: Zotero downloads each new version once for every copy that has the plugin, so we count the downloads of its most-downloaded recent release. Rounded. Plugins that update from outside GitHub count low.
18
DownloadsAll-time downloads of its release files from GitHub, counting every update. Installs from elsewhere aren't counted.
23
ReleasesVersions published on GitHub. Everyone who has the plugin downloads each one again, which adds up in Downloads.
2
StarsPeople who starred the repository on GitHub: a rough measure of interest.
1
ContributorsPeople who have committed code to the repository.
1
LicenceThe licence the code is published under, as GitHub reports it.
AGPL-3.0
B
Atlas gradeUse with care
because it launches programs on your computer
Applies to v0.1.16, released 24 Oct 2026Code checked · not yet tested in a live Zotero
Documentation in Chinese onlyOur summary is in English, but the plugin's own docs and support are in Chinese.
What we found in the codeSets the gradeThe worst finding in these three areas sets the grade.
Code transparencyReadable code, uploaded by the project's automated GitHub buildThe release file was uploaded by the project's automated GitHub build. We haven't yet rebuilt it from the source to compare.LowLow concern: normal for plugins that do this job. Listed so you know.
Updates
Doesn't update automatically: the update address is a placeholder
Where your data goesOnly contacts services we could identify2 addresses in 2 groups.LowLow concern: normal for plugins that do this job. Listed so you know.
AI services (1)
paddleocr.aistudio-app.com
On your computer (1)
127.0.0.1
Where we found it
paddleocr.aistudio-app.comprefs.js · line 1
pref('extensions.paddleocrrepair.baseURL', 'https://paddleocr.aistudio-app.com');
Powerful capabilitiesLaunches programs on your computer, and 3 moreMediumMedium concern: worth reading before you install. One medium finding makes the grade B.
Medium concern (1)
Launches programs on your computer
Low concern (3)
Uses the clipboardWorks with files on your computerUses Zotero's password manager
Where we found it
Launches programs on your computerrepair.js · line 160
const process=Cc['@mozilla.org/process/util;1'].createInstance(Ci.nsIProcess);
Before you installShown, not gradedFacts to help you decide. They don't change the grade.
Works withZotero 7, 8, 9, 10 · not 11 betaManual updates only
Zotero 7 ✓ worksZotero 8 ✓ worksZotero 9 ✓ worksZotero 10 ✓ worksZotero 11 beta ✗ doesn't work
What you'll needNothing extra detectedDetected automatically from its code
No further detail for this area yet.
MaintenanceActive · last release 24 Oct 20261 contributor
No further detail for this area yet.
LanguagesDocumentation in Chinese onlyInterface language not declared
No further detail for this area yet.
We report what we found in the code. Open any area for the evidence.How we gradeReport a problem

What it does

Written by AI from the README

Adds an invisible text layer to scanned PDFs using PaddleOCR and tidies highlighted quotations. It converts punctuation, removes stray spaces and fills in book details from the copyright page. OCR needs a PaddleOCR token and local Python.

Aimed at Chinese-language readers whose scanned books cannot be searched or highlighted, and whose CNKI papers copy out with English punctuation and extra spaces.

What you'll need

Detected automatically

We haven't detected any setup requirements. That isn't the same as none: check the developer's README.

Where your data goes

We found: only contacts services we could identify. 2 addresses in 2 groups.

AI services (1)
paddleocr.aistudio-app.com
On your computer (1)
127.0.0.1
Evidence · file and line
paddleocr.aistudio-app.comprefs.js · line 1
pref('extensions.paddleocrrepair.baseURL', 'https://paddleocr.aistudio-app.com');

Other plugins that do this

Matched on what they do

For the same job, work with Zotero 10 and graded B or better. Closest match first.

  • B
    Zotero OCR

    Runs Tesseract OCR on scanned PDFs and saves a searchable copy with a text layer, optionally with a note holding the text or hOCR files.

    Matches “add text layer to pdf” · 576,085 downloads · Active · Zotero 7–10
Compare all 2 side by side
How we pick these

By how closely what they do matches this plugin, using descriptions and the phrases people search with. Copies and forks of this plugin are listed under Forks and copies instead. No plugin pays to appear here.

Forks and copies

No forks listed.

The developer's response

The developer hasn't responded. Developers can reply here, and their reply sits next to our findings.I'm the developer

Ratings and reviews

What people who use it say. This is separate from the grade, which is what the code does, and never changes it.

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Install PDF OCR Helper
BUse with care
Before you install: It launches programs on your computer.Read the finding
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