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Open Source Python API to Add OCR to PDF Files

Free Python OCR API to automates the OCR process and facilitates the conversion of Scanned Image PDFs into fully searchable documents.

Optical Character Recognition (OCR) technology has revolutionized the way we handle and process documents, enabling us to extract valuable information efficiently. Among the many OCR tools available, OCRmyPDF stands out as a versatile and powerful Python library that combines ease of use with exceptional accuracy. OCRmyPDF is an open-source command-line tool and Python library designed specifically for adding OCR to existing PDF files. The library analyzes each page of a PDF file to determine the colorspace and resolution (DPI) needed to capture all of the information on that page without losing content.

The open source OCRmyPDF library supports a wide range of input formats, including scanned images, existing PDFs, and even DjVu files. It operates on the premise of "image plus text" and aims to produce high-quality output by preserving the original document's structure and formatting. The library employs PDF optimization techniques to reduce file size while maintaining the highest possible quality. By applying compression and down-sampling, it ensures that the resulting OCR-enabled PDF files are both efficient to store and quick to load.

OCRmyPDF utilizes the robust Tesseract OCR engine, which supports over 100 languages. Its advanced algorithms ensure accurate recognition of text, even from low-quality or distorted images. The library has provided support for generating a searchable PDF/A file from a regular PDF with ease. It also provides some image processing options, like deskew, which improves the appearance of files and the quality of OCR. When these are used, the OCR layer is grafted onto the processed image instead. Its comprehensive feature set, including support for multiple languages, PDF optimization, text layer control, and automated processing, makes it a valuable tool for businesses, researchers, archivists, and anyone dealing with large volumes of scanned documents.

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Getting Started with OCRmyPDF

The recommend way to install OCRmyPDF is using pip. Please use the following command for a smooth installation.

Install OCRmyPDF via pip

 pip install ocrmypdf

You can also install it manually; download the latest release files directly from GitHub repository.

PDF optimization using Python API

The open source OCRmyPDF library has provided support a very useful features to manage the size and quality of PDF documents inside Python applications. The library employs PDF optimization techniques to reduce file size while maintaining the highest possible quality. By applying compression and down-sampling, it ensures that the resulting OCR-enabled PDF files are both efficient to store and quick to load. OCRmyPDF provides several optimization options that you can customize based on your requirements. Some commonly used options include removing temporary files, applying JBIG2 compression, skipping adding the OCR, disabling lossless compression to maximize file size reduction and so on.

How to Optimize PDF Files using Python API?

import subprocess

def optimize_pdf_with_ocrmypdf(input_pdf_path, output_pdf_path):
    try:
        # OCRmyPDF command with optimization options
        command = ['ocrmypdf', '-l', 'eng', '--pdf-renderer', 'hocr', '--optimize', '0', input_pdf_path, output_pdf_path]
        
        # Execute the OCRmyPDF command
        subprocess.run(command, check=True)
        
        print("PDF optimization complete!")
    except subprocess.CalledProcessError as e:
        print(f"OCRmyPDF error: {e}")
        
# Example usage
input_pdf_path = 'input.pdf'
output_pdf_path = 'output.pdf'

optimize_pdf_with_ocrmypdf(input_pdf_path, output_pdf_path)

PDF Text Layer Integration via Python API

OCRmyPDF, an open-source library, provides a powerful solution for integrating text layers into PDF files, enhancing document accessibility and search-ability. The library adds a text layer containing OCR-generated text directly onto the PDF document, ensuring the preservation of the original layout. This feature enables full-text searching, copy-pasting, and text extraction. When working with PDF documents, having a text layer integrated within the file is highly advantageous. The text layer contains the recognized OCR-generated text, making the PDF searchable and allowing for easy copying and extraction of text. This integration preserves the original document layout while enabling text-based operations, enhancing document usability and efficiency.

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