Scanned paper documents, photographs of receipts, and flattened PDF contracts are essentially image files wrapped inside a PDF container. Because there is no underlying vector text, you cannot search (`Ctrl+F`), select, or copy text from them. Optical Character Recognition (OCR) solves this problem by analyzing image pixels and translating letter shapes into digital text.
How Web-Based OCR Works
Modern browser capabilities allow WebAssembly-powered OCR engines (like Tesseract.js) to process documents directly in client memory. The OCR process follows three key steps:
- Image Pre-processing: Binarizing and cleaning background noise on the document page to improve character contrast.
- Feature Extraction: Identifying glyph contours, font baselines, and individual character spaces.
- Text Recognition & Layer Generation: Converting detected shapes into machine-readable Unicode strings and overlaying an invisible text layer over the image.
Benefits of Client-Side OCR over Cloud Services
Traditional online OCR converters require uploading multi-page scanned documents to external cloud clusters. Scanned medical records, tax forms, and ID cards contain sensitive personal data. Using MyPDF Extract Text (OCR) ensures that OCR processing runs 100% locally inside your browser WebWorker thread, keeping your files completely confidential.
Extract Text from Scanned PDFs Safely
Convert images and scanned documents into searchable, copyable text offline.
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