Low-quality scans don't have to mean poor OCR results. Modern image processing technology can significantly improve recognition accuracy even on blurry, faded, or damaged documents.
Common Low-Quality Scan Issues
Understanding the problems helps select the right solutions:
- Blurry images — Motion blur or out-of-focus scanning
- Faded text — Old documents with light ink
- Low resolution — Scanned at dpi below 150
- Poor contrast — Light text on light backgrounds
- Damage — Water stains, tears, or folds
Image Enhancement Technology
PDFLocally.com applies intelligent preprocessing to improve recognition:
1. Auto-Contrast Adjustment
Automatically adjusts brightness and contrast to make text more distinct from background.
2. Sharpening Filters
Enhances edge definition to improve character recognition on blurry documents.
3. Noise Reduction
Removes speckles and artifacts that interfere with text recognition.
# Process low-quality scan with enhancement
pdflocally ocr --enhance --quality high input.pdf
# Features applied:
# - Contrast optimization
# - Sharpening filter
# - Noise reduction
# - Deskew correction"We had boxes of old faded contracts that were barely readable. PDFLocally's enhancement brought them back to life - 95% accuracy on documents that looked hopeless." — Archivist
Quality Enhancement Results
| Original Issue | Enhancement Applied | Accuracy Improvement |
|---|---|---|
| Blurry scan | Sharpening + deblur | +40% |
| Faded text | Contrast boost | +35% |
| Low resolution | Upscaling + sharpen | +25% |
| Poor contrast | Threshold adjustment | +45% |
Best Practices for Low-Quality Scans
- Enable enhancement — Always use image preprocessing for poor scans
- Check results — Review output for recognition errors
- Manual correction — Fix remaining errors in output document
- Re-scan if possible — Better original yields better results
Improve OCR Accuracy
Use PDFLocally's advanced image enhancement to achieve best OCR accuracy on low-quality scans.
Try FreeFrequently Asked Questions
Can OCR fix blurry or faded documents?
PDFLocally.com uses advanced image preprocessing to enhance low-quality scans. While extreme damage may have limits, most blurry, faded, or low-contrast documents can be significantly improved.
What resolution is needed for good OCR?
300 dpi is ideal, but PDFLocally can still achieve good results at 150 dpi with enhancement enabled.
How much does enhancement improve accuracy?
Improvement varies by document condition. Typical gains are 25-45% accuracy improvement on low-quality sources.