How the PDF OCR Tool Works
DocDox PDF OCR extracts readable text from scanned PDFs and image-based documents using Tesseract.js — a full optical character recognition engine compiled to WebAssembly that runs entirely in your browser. Scanned PDFs contain images of text rather than actual text data, making them unsearchable and impossible to copy from. OCR converts those image pixels back into machine-readable characters.
When you upload a scanned PDF, each page is rendered using PDF.js and passed through Tesseract's recognition pipeline. The engine identifies characters, words, lines, and paragraphs, reconstructing the document's text layout. Recognized text is presented organized by page, ready to copy or download as a .txt file.
Recognition accuracy depends on scan quality: documents scanned at 300 DPI or higher with good contrast produce highly accurate results. Handwritten text or very low-resolution scans may require manual correction. Because everything runs locally, even documents containing sensitive information — medical records, legal contracts, financial statements — can be processed safely.
Can it read handwritten text?
Tesseract has limited handwriting support. Printed text is reliably extracted; handwriting results vary significantly by clarity.
Is my document sent to any server?
No. Tesseract.js runs the OCR engine locally in your browser using WebAssembly.
What languages does OCR support?
The default model supports English. Multi-language support depends on which Tesseract language packs are loaded.