PDF file formats are a compact format widely used to create portable documents, reports, e-books, and more. Originally developed by Adobe in 1992, it has become a world standard.
PDF files can contain text, images, and tables, and can be generated by many office suites, document editors, apps, web services, and more.
Many users may need to extract and edit PDF content, such as text, images, and tables, or extract text highlights and annotations. If you are one of these users, this post is for you.
However, if you are looking for a free PDF editor programs, we got you covered in the following post:
In this post, we present the best free and open-source PDF OCR solutions. These alternatives can save you the cost of commercial PDF programs while still offering high-quality OCR capabilities.
Note that most of these tools require a fair amount of knowledge on how to run command-line applications.
1. OCRmyPDF: Search your PDFs with ease
OCRmyPDF is a free open-source command-line tool that adds an OCR text layer to scanned PDF files, allowing them to be searched or copy-pasted. It is already being used to scan and search millions of heavy PDF files.
Its features include:
- Generates a searchable PDF/A file from a regular PDF
- Places OCR text accurately below the image to ease copy / paste
- Keeps the exact resolution of the original embedded images
- When possible, inserts OCR information as a "lossless" operation without disrupting any other content
- Optimizes PDF images, often producing files smaller than the input file
- If requested, deskews and/or cleans the image before performing OCR
- Validates input and output files
- Distributes work across all available CPU cores
- Uses Tesseract OCR engine to recognize more than 100 languages
- Keeps your private data private.
- Scales properly to handle files with thousands of pages.
2. pd3f : PDF Text Extraction Tool
pd3f is a powerful free self-hosted PDF text extraction pipeline that utilizes state-of-the-art machine learning algorithms to reconstruct the original text. With the ability to OCR scanned PDFs using Tesseract and extract tables with Camelot and Tabula, pd3f is a versatile tool that can handle a variety of tasks.
As it uses Parsr, which accurately detects hierarchies of text and splits the text into words, lines, and paragraphs, pd3f-core takes it a step further by reconstructing the original continuous text, removing hyphens, new lines, and spaces with ease.
Thanks to its advanced language models, pd3f offers support for multiple languages including German, English, Spanish, French, and Italian. And with its intuitive Web-based GUI and Flask-based microservice (API), It also offers a user-friendly experience that is unparalleled in the industry.
3. PDF-TOOLBOX: Multi-purpose PDF editing tool
This is an amazing open-source PDF toolbox that allows you to edit PDF files, convert them into editable text format, merge and split PDF files, add watermarks, encrypt and decrypt PDFs, and even convert PDF files into audiobooks.
Despite having a command-line interface, it is fairly easy to use, with straightforward commands and shortcuts.
4. pdfocr: Search PDF files
pdfocr adds an OCR text layer to scanned PDF files, allowing them to be searched. It currently depends on Ruby 1.8.7 or above, and uses ocropus, cuneiform, or tesseract for performing OCR.
5. OCR-Table: Extract Tables from PDF files
This project aims to extract tables from scanned image PDFs using Optical Character Recognition.
This is a simple python script that executes tesseract OCR on a multipage PDF.
Each page of the PDF is converted into an image, each image is converted to text, and all text files are concatenated to produce the final output.
The script allows you to specify ImageMagick parameters in the image conversion, along with some tesseract parameters for the OCR.
PDF2TXT is a program that converts PDF files to plain text (TXT) format without losing data or formatting. It can convert multiple files at once, and can be used with a user-friendly GUI or a versatile console-mode command line.
The resulting text files can be viewed or edited in any text editor or viewing program. PDF2TXT also includes a plain text view for easy reading of PDF files. It is compatible with all versions of Windows.
Remarks allows you to easily extract PDF annotations and text highlights, and convert them into Markdown, PDF, PNG, or even SVG files. It depends heavily on the PyMuPDF and Shapely libraries.
borb is a pure Python library for reading, writing, and manipulating PDF documents. It represents a PDF document as a JSON-like data structure of nested lists, dictionaries, and primitives (numbers, strings, booleans, etc.).
borb's features include:
- Reading a PDF and extracting meta-information
- Changing meta-information
- Extracting text from a PDF
- Extracting images from a PDF
- Changing images in a PDF
- Adding annotations (notes, links, etc) to a PDF
- Adding text to a PDF
- Adding tables to a PDF
- Adding lists to a PDF
- Using a PageLayout manager
Alchemy is an open-source file converter (built on Electron and React). It also supports operations like merging files together into one single PDF file.
Alchemy features include:
- Beautifully simple. Super easy, drag-and-drop interface for converting/merging files
- Merge files. Merge multiple images into one PDF, you can even change the file order
- Convert files. Batch-convert multiple files to a variety of file types
12. Dangerzone: Convert Dangerous PDF files into Safe ones
Dangerzone empowers you to transform potentially harmful PDFs, office documents, and images into secure PDFs across Windows, Linux, and macOS platforms.
It boasts the ability to convert various file formats into PDF, including but not limited to MS Docs, Excel files, PowerPoint files, Open Document Format files for documents (Text: ODT), ODS, ODG, and ODP. Additionally, it allows you to effortlessly convert images into PDF files.
What does Dangerzone do?
- Sandboxes don't have network access, so if a malicious document can compromise one, it can't phone home
- Dangerzone can optionally OCR the safe PDFs it creates, so it will have a text layer again
- Dangerzone compresses the safe PDF to reduce file size
- After converting, Dangerzone lets you open the safe PDF in the PDF viewer of your choice, which allows you to open PDFs and office docs in Dangerzone by default, so you never accidentally open a dangerous document
PyMuPDF is a feature-rich Python library that provides bindings for the MuPDF app. It adds functionality to PDF viewing, including text and image extractions, searching large PDF files, and converting to and from PDF files with support for many other formats. Additionally, it has a strong OCR system with Tesseract support.
If you know of any other open-source PDF OCR solutions that we did not mention here, please let us know.