High-Accuracy OCR (Image/PDF)
OCR-focused tool for extracting text from images and PDFs with high accuracy. Local-first processing keeps sensitive documents private.
How to Use
- 1
Upload an image or PDF. For PDFs, embedded text extraction is attempted first, then OCR is used for image-only pages.
- 2
Choose OCR language and OCR quality (Balanced or High Quality).
- 3
Click Run OCR to start extraction.
- 4
Review the extracted text, edit if needed, then copy or save as TXT.
Key Features
- ✓Image + PDF workflow focused purely on OCR extraction.
- ✓Local-first execution: OCR inference runs inside your browser whenever possible.
- ✓Smart PDF handling: embedded text extraction first, OCR fallback only where needed for speed.
- ✓High-quality mode: stronger preprocessing and higher render scale for better recognition on difficult inputs.
- ✓Input preview: immediately verify which image was dropped before running OCR.
- ✓Progress visibility: OCR progress shown with percentage.
FAQ
Q. Are my images or PDFs uploaded to a server?
A. No. OCR is processed locally as much as possible and there is no file-upload API in this tool. Initial model downloads are required for first-time use.
Q. Why can large PDFs feel slow?
A. Image-only PDFs require per-page OCR. Splitting files and choosing the correct OCR language can improve both speed and accuracy.
Q. How can I improve OCR accuracy?
A. Use Ultra Quality mode for small text, noisy scans, or low-contrast pages. It runs upscaling, adaptive binarization, and multi-PSM OCR passes, then keeps the best result. Cropping and deskewing also help significantly.
Q. When should I use High Quality mode?
A. Use it for difficult images with blur, compression artifacts, or tiny fonts. For normal documents, Balanced mode is usually faster.
Q. Why is the first run slower?
A. OCR assets are downloaded and cached on first use. Subsequent runs start much faster.
Technical Deep Dive
OCR uses Tesseract.js. For PDFs, the system first reads embedded text with pdf.js and only falls back to page-image OCR when needed, giving better performance on document PDFs.
High-quality mode applies image preprocessing with adaptive thresholding plus higher PDF render scale to improve recognition quality on noisy documents.
Ultra Quality mode compares multiple preprocessing variants (upsampled, Otsu-binarized, adaptive-binarized) across multiple page segmentation modes and selects the highest-scoring OCR output.
OCR workers are reused per language to reduce repeated initialization overhead during consecutive runs.
Model caching is enabled so repeat usage is significantly faster.
Privacy & Security
Input content (image pixels and PDF text) is processed only inside the tool and is not stored on servers.
OCR model downloads happen from public model sources, but your document content itself is not transmitted.
Output text lives in browser memory and stays local unless you explicitly copy or export it.