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Extract Text From Images And PDFs With gImageReader On Linux

Have you ever faced a situation where you need to extract text from a piece of paper or an image? It is indeed a common scenario in the office and even at home. You may need to extract text from a scanned document image, a piece of paper, or old research work.

You need to type the whole thing by your hand using a text editor. This is extremely time-consuming.

There is a better solution for that.

In this post, I am going to introduce you to a tool that works like a charm and extracts text from a PDF or picture easily. It’s an OCR (Optical Character Recognition) tool that uses Tesseract Open Source OCR Engine.

Tesseract is an open-source OCR engine library that helps you to extract text from images. But it’s a command-line application so we need a GUI for that.

This is where gImageReader comes into play.

What Is gImageReader?


gImageReader is a front-end GUI application for Tesseract Open-source OCR Engine. Tesseract itself is a CLI tool so we need a GUI to utilize it.

This is where gImageReader comes in handy. It offers you a beautiful Graphical User Interface that helps you to utilize Tesseract OCR Engine. As Tesseract supports several languages and Unicode characters, you can easily scan through documents like PDFs and images to extract text.

gImageReader is a cross-platform application that works in Linux and Windows as well. It is one of the best open-source OCR tools available in the market.

Key Features Of gImageReader

gImageReader offers a handy amount of features to extract text more easily and effectively.

Supports a variety of Image Files And PDF

gImageReader supports a variety of image formats and PDF documents. You can import files directly from the scanner, the disk, the clipboard, and the screenshot. gImageReader allows you to import multiple files at once. You just need to import your files and extract text with one click.

Process multiple files in one go

gImageReader can process multiple files in one click. You need to import all the files, select Plain text or hOCR, PDF as the output parameter, and click the Recognize all button to start processing. If you want additional changes, click the Down arrow button right next to the Recognize all button.

Basic Image Adjustment Controls

gImageReader - Image Controls

gImageReader offers image adjustment controls to manually adjust the Brightness, Contrast, Resolution, and Invert Colors. You can also rotate the image to straighten the lines to help gImageReader performs better.

Auto and Manual detection of the target area

You can either scan the whole image or use the Autodetect layout option to automatically detect the targeted area. You can also manually select multiple areas using the mouse. Hold Ctrl and drag the mouse to select areas.

gImageReader - Area Detection

Extract to Plain Text, hOCR, and PDF

You can extract Plain text and save it as a TXT file or you can scan for hOCR formatted text to save it as an HTML file or export it as a PDF or ODT file.

Multilingual Support

gImageReader supports multiple languages which means you can extract text from different languages. You need to install the appropriate language packs to work. As gImageReader uses the Tesseract OCR Engine, you need to install Tesseract OCR language packs. It also supports Unicode characters.

Spellcheck Support

gImageReader also has Spellcheck support. This feature is a very important one. If your images are not clear enough, extracting text can get messy. You may find incorrect words, missing words, or misspelled words. If you scan multiple documents then it will be hard to find those mistakes. gImageReader helps you to identify any incorrect spelling from the extracted text.

Various Page Segmentation Mode

Page segmentation mode is used for a better understanding of the document. You can help gImageReader by telling it how the documents should be scanned and prepared. There are 10 types of segmentation options available. Use these Page segmentation options according to your needs

gImageReader - Page Segmentation Mode

How To Install gImageReader On Ubuntu/Linux Mint/Zorin OS?

As I said at beginning of this post, gImageReader is a GUI that uses the Tesseract OCR engine and Tesseract OCR Language packages. So we need to install these packages first. Use the following command to install the Tesseract OCR engine and the English language pack. The following command should work on Ubuntu or any Ubuntu-based distribution like Linux Mint, or Zorin OS.

Tesseract OCR Engine can be found on Ubuntu Universe Repository. If Universe Repository is disabled, you will not find the packages. To activate the Universe Repository, use the following command.

sudo add-apt-repository universe

Now, install Tesseract OCR Engine and English language pack using the following command.

sudo apt install tesseract-ocr tesseract-ocr-eng

You can install gImageReader directly from Ubuntu Universe Repository. But I prefer using the PPA from the developer to always get the latest update quickly. Use the following command to add the PPA and install gImageReader.

sudo add-apt-repository ppa:sandromani/gimagereader
sudo apt update
sudo apt install gimagereader

How To Uninstall gImageReader On Ubuntu/Linux Mint/Zorin OS?

If you want to uninstall gImageReader from the system, use the following commands to do so. The following commands will remove the gImageReader, unwanted additional packages, and the PPA from the system.

sudo apt-get remove gimagereader -y
sudo apt-get autoremove
sudo add-apt-repository -r ppa:sandromani/gimagereader

Pros And Cons

Free & open-source Cannot change the order of the elements inside the hOCR tree.
Easy user interface Lack of advanced image correction options.
Basic image correction support. May find incorrect words if the picture is blurry.
Process multiple documents at once.
Supports a variety of image files and PDFs.
Character whitelist/blacklist support.
Export as hOCR HTML, PDF, and Plain text.


gImageReader might not be the best one if you use proprietary software like ABBYY Finereader. But if you like open-source software then you should try gImageReader. It uses one of the best OCR engines and gives you a handful of features to do the job.

It is easy to use and offers a beautiful user interface. If you find any difficulties using the software or face any issues during the installation, feel free to ask in the comment section below. I will be very happy to help you out.

And if you find this post helpful, don’t forget to share this with your friends. Until then, have a great day.

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