Tesseract is an open source optical character recognition (OCR) engine that allows you to extract text from images. It can be highly useful for digitizing printed documents and analyzing images containing text.
In this comprehensive guide, I will walk you through the entire process of installing and using Tesseract on Windows, from downloading the installer to running Tesseract commands for text recognition.
Downloading and Installing Tesseract
Here are the step-by-step instructions to download and install Tesseract on your Windows machine:
1. Download the Installer
First, you need to download the Windows installer for Tesseract from its GitHub repository. Be sure to pick the relevant installer for your system – 32 bit or 64 bit.
Once the installer is downloaded, navigate to the location where it is saved on your system. This is usually the Downloads folder.
2. Run the Tesseract Installer
Double click on the Tesseract installer file. This will launch the setup wizard.
Click ‘Next‘ to begin the installation process.
3. Accept the License Agreement
The next step is to accept the license agreement to proceed further. Go through the agreement text and click ‘I Agree‘ if you agree with the terms and conditions.
4. Select Installation Type
Now you need to decide whether you want to install Tesseract for yourself only or for all users on the system.
Choose ‘Install for myself‘ if you want Tesseract available just for your user account. Select ‘Install for everyone‘ to have it accessible system-wide for all users.
For this guide, I will install Tesseract for all users. Click ‘Next‘ once you have selected the desired installation type.
5. Change Install Location (Optional)
By default, Tesseract gets installed in C:\Program Files\Tesseract-OCR
. But you can change this location if you want.
To change the install directory, click the folder icon next to the location text box. Then browse to your desired folder and select it.
I will stick with the default location for this demo. Click ‘Next‘.
6. Install Additional Languages (Optional)
Tesseract supports OCR in a wide variety of languages. By default, it includes English language support.
You can choose to install support for additional languages at this step. This will allow Tesseract to recognize text in other languages as well.
I will skip adding other languages for now. Select ‘Next‘.
Note: You can always install language support later on as well after the initial setup is complete.
7. Create Start Menu Shortcuts
Finally, decide if you want Tesseract to create Start menu shortcuts or not. This will add handy shortcut links to launch Tesseract and access documentation.
Check the box next to "Do not create Start Menu shortcuts" if you don‘t need these.
Click the ‘Install‘ button once you have made your choice. This will proceed with the final installation steps.
8. Complete the Installation
Allow some time for all Tesseract components and libraries to be installed successfully. The setup wizard will show the installation progress.
Once done, you will see the completion screen. Click ‘Finish‘ to close the setup wizard.
This completes the process of downloading and installing Tesseract OCR on your Windows machine. Next, we will configure the PATH environment variable.
Setting up PATH Environment Variable
In order for Tesseract to be accessible from the command line, you need to add its installed directory to the system‘s PATH environment variable. Here is how to do it:
1. Copy the Installed Path
First, open the folder where Tesseract is installed. For me, this is C:\Program Files\Tesseract-OCR
.
Then copy the path from the address bar:
Alternatively, you can open the command prompt and type where tesseract
to find the installed path.
2. Open Environment Variables
Next, right click on This PC and select Properties. This opens up the System settings.
Go to Advanced system settings > Environment Variables.
3. Edit PATH Variable
Under System Variables, select the PATH entry and click Edit.
Then click New and paste the Tesseract installed path you copied earlier. Click OK to save the updated PATH.
4. Verifying the Installation
With PATH setup, open cmd and run:
tesseract -v
This will print the version details if Tesseract is successfully installed:
And that‘s it! Tesseract is now fully installed and configured.
Using Tesseract for OCR
Now that we have Tesseract available in our system, let‘s look at how to put it to use for text recognition purposes.
For extracting text with Tesseract, you generally need to:
- Have an image file containing text – scanned document, screenshot, photo etc.
- Run tesseract command specifying input image and output file
Let‘s understand it better with an example image:
This is a screenshot of some handwritten text. We will use Tesseract to recognize this text and extract it out into a separate text file.
Here is the command to achieve OCR on this:
tesseract sample.jpg output
This will process ‘sample.jpg‘, and save the recognized text in ‘output.txt‘. Pretty simple!
The text extraction works quite well, though accuracy depends on the input image quality. Some key pointers:
- Clear images with good contrast and resolution give best results
- Images containing only text work better compared to natural scenes
- Screenshots and scans may need preprocessing before being fed to Tesseract
Let‘s see the output text file containing extracted text from our sample image:
So with just a single command, Tesseract automatically recognized all the handwritten text with good accuracy!
Customizing Tesseract Usage
By default, Tesseract runs with basic configurations suitable for most use cases. But its usage can be customized further for advanced OCR requirements:
Specify Language
The -l <lang>
parameter explicitly defines the recognition language:
tesseract sample.png output -l eng
This forces English language dictionary usage.
Configure Page Segmentation
Use -psm
to set page segmentation modes – controls how images are processed and text is extracted out:
tesseract sample.jpg output --psm 3
Auto page segmentation with orientation detection.
See Tesseract documentation for details on all possible configurations. There are abundant tuning options!
Improve Accuracy
Some techniques to improve OCR accuracy with Tesseract include:
- Image enhancement – adjust contrast, sharpness etc.
- Removing background noise, clutter
- Handle skewed documents with deskew pre-processing
- Training Tesseract for specific use case with customized data
With the right tuning and data quality, Tesseract can extract text from images with near perfect accuracy!
Integrating Tesseract with Programming Languages
So far I have covered using Tesseract through command line, which provides an easy way to perform OCR tasks in a standalone manner.
Additionally, Tesseract exposes APIs that allow integrating its recognition capabilities within a wide range of programming languages:
This makes it suitable for incorporating OCR functionality within your own applications as well.
Some examples:
- Build a document scanner app with C# and Tesseract
- Create a PDF text extractor tool in Python using Tesseract bindings
- Leverage Tesseract OCR in your Nodejs server for processing user-uploaded images
Since Tesseract is open source and provides versatile integration options, the possibilities are endless!
Conclusion
In this guide, you learned how to:
- Download and install Tesseract OCR engine on Windows
- Configure Tesseract by setting up environment variable
- Use basic Tesseract commands for text recognition from images
- Customize parameters for advanced OCR requirements
- Integrate Tesseract APIs in programming languages like Python and C#
Tesseract is an immensely useful tool for extracting text from visual data. With robust OCR capabilities, integration flexibility, and active development community – it is certainly a must-have utility!
I hope you found this tutorial helpful in getting started with leveraging Tesseract for your own text processing needs. Let me know if you have any other questions.