Utilities

Excellent Utilities: OCRmyPDF – add OCR text layer to scanned PDFs

Last Updated on May 22, 2022

This is a series highlighting best-of-breed utilities. We cover a wide range of utilities including tools that boost your productivity, help you manage your workflow, and lots more besides. There’s a complete list of the tools in this series in the Summary section.

Optical Character Recognition (OCR) is a visual recognition process that turns printed or written text into an electronic character-based file. This makes the document searchable and offers the ability to copy-paste its contents.

PDF is generally considered to be an excellent format for storing and exchanging scanned documents. Unfortunately, PDFs aren’t trivial to modify. OCRmyPDF makes it easy to apply image processing and OCR to existing PDFs. The program add an OCR text layer to scanned PDF files. It’s a command-line only affair.

Let’s get an important distinction out of the way. If you create a PDF document from an electronic source, there will already be an OCR layer applied. Native PDF files have an internal structure that can be read and interpreted. These “generated” PDF documents already contain characters that have an electronic character designation. The most popular office suite for Linux is LibreOffice. That suite automatically applies a text layer to documents exported to the PDF format. For this scenario, you don’t need OCRmyPDF.

PDF documents are also created by scanning a paper document into an electronic format. Typically, this is with a flatbed scanner. The scanner takes a “snapshot” of the paper document. This snapshot is turned into a PDF (or another format such as JPG and TIFF). This is a “scanned” PDF document which often won’t have an OCR layer. Want to add that text layer? Step forward OCRmyPDF.

Installation

Installation procedure will depend on the Linux distro you’re using. On my Arch based system, installation is trivial, as there’s a package in the Arch User Repository.

Installing the package pulls in a number of other programs including tesseract, img2pdf, pngquant, unpaper, and various Python packages.

You’ll also need a language pack.

$ sudo pacman -S tesseract-data-eng

I’m using the English language pack for Tesseract. But Tesseract supports most languages. Just install the relevant language pack(s) for your requirements. And there’s support for multilingual documents.

Next page: Page 2 – In Operation

Pages in this article:
Page 1 – Introduction / Installation
Page 2 – In Operation
Page 3 – Summary


Complete list of articles in this series:

Excellent Utilities
AES CryptEncrypt files using the Advanced Encryption Standard
AnanicyShell daemon created to manage processes’ IO and CPU priorities
brootNext gen tree explorer and customizable launcher
CerebroFast application launcher
cheat.shCommunity driven unified cheat sheet
CopyQAdvanced clipboard manager
crocSecurely transfer files and folders from the command-line
DeskreenLive streaming your desktop to a web browser
dufDisk usage utility with more polished presentation than the classic df
ezaA turbo-charged alternative to the venerable ls command
Extension ManagerBrowse, install and manage GNOME Shell Extensions
fdWonderful alternative to the venerable find
fkillKill processes quick and easy
fontpreviewQuickly search and preview fonts
horcruxFile splitter with encryption and redundancy
KoohaSimple screen recorder
KOReaderDocument viewer for a wide variety of file formats
ImagineA simple yet effective image optimization tool
LanguageToolStyle and grammar checker for 30+ languages
Liquid PromptAdaptive prompt for Bash & Zsh
lnavAdvanced log file viewer for the small-scale; great for troubleshooting
lsdLike exa, lsd is a turbo-charged alternative to ls
Mark TextSimple and elegant Markdown editor
McFlyNavigate through your bash shell history
mdlessFormatted and highlighted view of Markdown files
notiMonitors a command or process and triggers a notification
NushellFlexible cross-platform shell with a modern feel
nvitopGPU process management for NVIDIA graphics cards
OCRmyPDFAdd OCR text layer to scanned PDFs
Oh My ZshFramework to manage your Zsh configuration
PaperworkDesigned to simplify the management of your paperwork
pastelGenerate, analyze, convert and manipulate colors
PDF Mix ToolPerform common editing operations on PDF files
pecoSimple interactive filtering tool that's remarkably useful
ripgrepRecursively search directories for a regex pattern
RnoteSketch and take handwritten notes
scrcpyDisplay and control Android devices
StickySimulates the traditional “sticky note” style stationery on your desktop
tldrSimplified and community-driven man pages
tmuxA terminal multiplexer that offers a massive boost to your workflow
TuskAn unofficial Evernote client with bags of potential
UlauncherSublime application launcher
WatsonTrack the time spent on projects
Whoogle SearchSelf-hosted and privacy-focused metasearch engine
ZellijTerminal workspace with batteries included
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