PDF to Text Converter: Scanned Raster OCR & Digital Vector Extraction
PDFs come in two distinct technical formats: digitally generated vector PDFs and scanned image bitmaps. Understand how our dual-pipeline handles both document types seamlessly.
Upload your PDF document
Extract text from single pages or multi-page documents up to 50 MB with asynchronous worker queues.
1. Digital Vector PDFs vs. Scanned Raster PDFs
Before processing a PDF, it is essential to distinguish between the two structural formats in which PDFs are created:
Digital Native Vector PDFs
Created directly by word processors (Microsoft Word, Google Docs, LaTeX, Adobe InDesign). These files contain an internal font glyph stream. Text can be copied directly without executing visual OCR, achieving instantaneous, 100% character precision.
Scanned Image (Raster) PDFs
Created by office flatbed scanners or smartphone scanning apps. The PDF is simply a container wrapping full-page bitmap images (JPEG or TIFF streams). It contains no underlying text characters and requires deep computer vision OCR to reconstruct words.
2. How ScanText Handles PDF Documents Under the Hood
To give you the fastest speed and highest quality, our backend executes an automated two-stage analysis on every uploaded PDF:
- Native Stream Inspection: The engine examines the PDF stream. If digital text layers are detected, it extracts characters directly in milliseconds.
- Rasterization & OCR Fallback: If no digital text layer exists (or if characters are embedded as drawn outlines), each PDF page is rasterized at 300 DPI using
pdf2image(Poppler) and dispatched page-by-page to the Tesseract 5 LSTM neural network.
3. Asynchronous Worker Architecture for Long Documents
Converting a 20-page or 50-page scanned PDF requires substantial CPU rasterization and neural processing that would exceed standard 30-second HTTP gateway timeouts.
ScanText uses an asynchronous queue powered by Celery & Redis. Multi-page jobs receive a tracking UUID and execute in dedicated background worker processes. The frontend polls progress in real time (e.g. "Processing Page 4 of 12") with zero browser freeze.
PDF Tier Limits & Specifications
| Feature | Anonymous & Free Tier | Pro Tier ($19/mo) |
|---|---|---|
| Max File Size | 10 MB | 50 MB |
| Max PDF Page Count | 5 pages per file | Up to 100 pages |
| Daily Conversions | 5 conversions / day | Unlimited / 1,000 / day |
| Worker Priority | Standard Queue | Priority High-Speed Queue |