How to Extract Text from Scanned PDFs & Photos with In-Browser OCR
Opening a scanned PDF or photograph of a document and trying to highlight or copy text often yields nothing: the cursor will not select anything because the computer sees the file as a single flat image. Manually retyping pages of text is tedious and error-prone.
Optical Character Recognition (OCR) solves this problem by analyzing the shapes of dark pixels, grouping them into letters, words, and sentences, and outputting editable text. Here is how OCR works in modern browsers and how to extract text from your files without compromising confidentiality.
How modern in-browser OCR works
Historically, OCR required installing bulky desktop software or uploading documents to third-party cloud servers. Today, lightweight neural network engines (such as Tesseract WebAssembly) run directly inside your browser tab:
- Binarization & Denoising: The image is converted to monochrome. High-frequency digital noise and background color gradients are stripped away.
- Line & Word Detection: The algorithm identifies horizontal baselines, character spacing, and paragraph margins.
- Character Classification: Neural feature extractors match letter outlines against trained multilingual language fonts.
- Spellchecking & Language Models: Contextual dictionaries disambiguate similar characters (such as the numeral '1', uppercase 'I', and lowercase 'l') based on grammar patterns.
How to extract text step-by-step
For single images or photographed pages:
- Open Image to Text (OCR).
- Drag and drop your JPG, PNG, or WebP screenshot.
- The engine processes the image locally and outputs clean, copyable text in the output box.
- Click Copy Text or Download .TXT.
For multi-page scanned PDF documents:
If you have a multi-page PDF, you can convert the entire document into an editable Microsoft Word document with tables and formatting preserved using PDF to Word, or ask questions directly against the document's content using Chat with PDF.
Tips for 99%+ OCR accuracy
- Straighten tilted pages: If the document is rotated by more than 5 degrees, letter baselines skew and accuracy drops significantly. Straighten the photo before running OCR.
- Ensure at least 200 DPI: Low-resolution phone thumbnails (below 1000 pixels wide) cause characters like 'e' and 'o' to blend together.
- Avoid harsh shadows: Strong creases or diagonal shadows across text lines confuse the binarization engine. Use diffuse lighting when photographing documents.
Privacy advantage of local processing
Scanned documents often include confidential personal records: medical diagnoses, bank account numbers, tax filings, or legal agreements. Cloud-based OCR services store copies of your documents on remote servers for processing. In File Studio, the OCR model runs inside your browser sandbox—your confidential records never leave your device.