Why Receipts Are Harder Than Documents
The Text Extractor uses Tesseract.js v4, which achieves 98-99% accuracy on clean digital documents. Real-world receipts present harder challenges:Thermal paper fading: Thermal printer receipts fade when exposed to heat, sunlight, or wallet friction. A 6-month-old grocery receipt may have text that is barely legible. OCR accuracy on faded receipts can drop to 60-70%.
Non-standard fonts: Cash registers use a variety of dot-matrix and thermal printer fonts where numerals like 1 and 7, or 0 and O, are ambiguous even to trained humans.
Physical distortion: A crumpled receipt photographed on a desk has curved text lines that can confuse Tesseract's line segmentation.
Step-by-Step for Accurate Receipt OCR
1. Use document scanner mode on your phone. iPhone (iOS 11+): Notes app, camera, Document mode. Android: Google Drive, + button, Scan. These modes apply automatic perspective correction and contrast enhancement.2. Maximize contrast before uploading. In your phone's photo editor, increase contrast by +30 and brightness by +10. If the receipt has low ink saturation, increase shadows to bring up faded areas.
3. Crop to the text area. Eliminate table surfaces, shadows, and surrounding context. Tesseract's layout analysis works better when the input is cropped close to the text.
4. Check critical numbers manually. For expense reports and accounting, always verify totals, dates, and vendor names against the physical receipt.
What OCR Extracts Well vs. Poorly on Receipts
| Data type | OCR reliability | Notes |
|---|---|---|
| Vendor name | High | Usually large, clear text |
| Date | High | Standard formats recognized well |
| Total amount | Medium-High | Verify decimal placement |
| Line items | Medium | Multiple columns cause layout errors |
| Tax breakdown | Medium | Small text, dense layout |