OCR PDF — Recognize Text in Scanned Documents
Transform scanned paper documents, receipts, and book photos into searchable, editable text using advanced in-browser Optical Character Recognition.
How to Perform OCR on a PDF
Transform scanned paper documents, receipts, and book photos into searchable, editable text using advanced in-browser Optical Character Recognition.
Upload Scanned PDF
Drag and drop your scanned document or image-based PDF into the OCR workspace.
Select Document Language
Choose the primary language (English, Arabic, multilingual) for optimal character recognition.
Process Text Recognition
Our client-side neural recognition engine scans glyph patterns and reconstructs words.
Copy or Download Text
Copy recognized text to your clipboard or download a searchable PDF or TXT file.
Why Use OCR with Khalasna?
100% In-Browser Recognition
Neural OCR models run locally via WebAssembly without uploading confidential scans to cloud servers.
Multi-Language Support
High-accuracy character recognition across English, Arabic, Latin, and modern scripts.
Searchable PDF Output
Injects an invisible text layer behind scanned images, making them fully searchable and selectable.
Preserves Page Layout
Maps recognized text directly to the original bounding boxes of scanned headings and paragraphs.
Technical Architecture: WebAssembly Neural OCR Pipelines
Optical Character Recognition (OCR) transforms raster pixel matrices of scanned pages into structured Unicode text. Khalasna executes OCR client-side using WebAssembly-compiled neural network models (Tesseract.js engine with SIMD acceleration). When a scanned PDF page is loaded, the engine renders it onto a high-resolution canvas, converts color channels into grayscale, and applies adaptive thresholding (Otsu binarization) to separate text ink from paper background noise. A deep neural network analyzes character connected components and word bounding boxes, resolving complex ligatures, font variations, and skew angles. For searchable PDF output, the engine constructs an invisible text layer using the 3 Tr rendering mode, positioning searchable text directly beneath the scanned raster image. The entire compute workload runs on your device's multi-core CPU using Web Workers, ensuring sensitive contracts and personal identity documents remain strictly private.
Common Applications for OCR PDF
Digitizing Paper Archives
Convert filing cabinets of old paper contracts and receipts into indexed, searchable digital archives.
Academic & Library Research
Extract searchable citations and quotes from scanned historical manuscripts and library books.
Legal Discovery & Invoicing
Search large bundles of scanned court evidence, briefs, and invoices by keyword instantly.
Frequently Asked Questions
Are my scanned documents sent to any external server?
+
Are my scanned documents sent to any external server?
+No. The OCR neural model executes entirely inside your browser using WebAssembly. Your documents never leave your computer.
Does OCR support Arabic script recognition?
+
Does OCR support Arabic script recognition?
+Yes, our OCR engine includes specialized linguistic models trained on Arabic character shapes and ligatures.
How clean does the scanned document need to be?
+
How clean does the scanned document need to be?
+Higher resolution scans (300 DPI) with good lighting produce the highest accuracy, but our engine includes contrast enhancement for phone photos.
Can I download the result as a searchable PDF?
+
Can I download the result as a searchable PDF?
+Yes, you can export a searchable PDF with an underlying text layer or download plain text.
Is there any charge for using OCR on Khalasna?
+
Is there any charge for using OCR on Khalasna?
+No, our OCR utility is completely free to use without subscriptions or usage fees.