OCRopus

OCRopus is an open-source optical character recognition (OCR) system and document analysis framework. It is designed as a modular toolkit for building end-to-end OCR pipelines and as a research platform for experimenting with layout analysis, text-line recognition, and post-processing.

The system structures processing as a sequence of interchangeable components. A page layout analysis module identifies regions such as text blocks and images; a segmentation module isolates lines of text; a line recognizer converts images of lines into text. Post-processing applies language models, dictionaries, and correction strategies to improve overall accuracy. The architecture emphasizes flexibility, allowing researchers and developers to substitute or extend components for specific scripts, languages, or font styles.

Recognition in OCRopus typically relies on machine learning approaches to map image features to character sequences. The framework provides tools for training custom models from labeled data, enabling adaptation to new languages, fonts, and handwriting styles. It supports experimentation with different recognition algorithms and post-processing techniques within a cohesive workflow.

History and status notes: OCRopus originated as an open-source project developed and released by researchers associated with Google and has since been maintained by the broader community. It has been used in academic settings to study document image analysis and OCR, contributing to research on layout analysis, segmentation, and neural-network–based recognition. While it has influenced subsequent OCR work, development activity has varied over time, with newer systems emerging alongside OCRopus.