OCR accuracy depends heavily on image quality and preparation. Follow these tips to maximize text recognition accuracy.
Image Quality Matters Most
Resolution
- Minimum: 150 DPI
- Recommended: 300 DPI
- Best: 300-600 DPI
Higher resolution = more detail = better recognition.
Sharpness
- Ensure text is in focus
- Avoid motion blur
- Use tripod or stable surface for scanning
Contrast
- Dark text on light background works best
- Avoid gray-on-gray scenarios
- Increase contrast if possible before OCR
Lighting
- Even, diffuse lighting
- Avoid shadows across text
- No bright spots or glare
- Natural daylight often works best
Document Preparation
Physical Documents
- Flatten curved pages
- Clean scanning surface
- Remove stains if possible
- Align straight on scanner
Photos
- Shoot perpendicular to surface
- Fill frame with text area
- Avoid perspective distortion
- Use grid overlay if available
Best Practices Checklist
| Factor | Optimal | Acceptable | Poor |
|---|---|---|---|
| Resolution | 300+ DPI | 150-300 DPI | <150 DPI |
| Lighting | Even | Some variation | Shadows/glare |
| Contrast | High | Medium | Low |
| Focus | Sharp | Mostly sharp | Blurry |
| Orientation | Straight | <5° tilt | >5° tilt |
Troubleshooting Poor Results
Gibberish Output
- Image might be too low resolution
- Try increasing contrast
- Ensure correct language is selected
Missing Characters
- Check for shadows or glare on those areas
- Very small text may not recognize
- Try cropping to smaller region
Wrong Characters
- Similar-looking letters confused (0 vs O, 1 vs l)
- Review and manually correct
- Better image quality helps
When OCR Struggles
- Handwriting (varies by clarity)
- Decorative fonts
- Very small text
- Low contrast
- Degraded/aged documents
Conclusion
Better input = better output. Follow these tips for Rune's Image to Text (OCR) to get the most accurate results.