OCR - Image Text Recognition (Local)#

Extract text from images using Tesseract.js. 100% local run, no API key required. Supports Chinese and English.

Quick start#

bash

node {baseDir}/scripts/ocr.js /path/to/image.jpg
node {baseDir}/scripts/ocr.js /path/to/image.png --lang chi_sim
node {baseDir}/scripts/ocr.js /path/to/image.jpg --lang chi_tra+eng

Options#

• --lang <langs>: Language codes (default: chi_sim+eng)
  • chi_sim - Simplified Chinese
  • chi_tra - Traditional Chinese
  • eng - English
  • Combine with +: chi_sim+eng
• --json: Output as JSON instead of plain text

Examples#

bash

# Recognize Chinese screenshot
node {baseDir}/scripts/ocr.js screenshot.png

# Recognize English document
node {baseDir}/scripts/ocr.js document.jpg --lang eng

# Mixed Chinese + English
node {baseDir}/scripts/ocr.js mixed.png --lang chi_sim+eng

Notes#

• Language data is stored in {baseDir}/scripts/tessdata/
• First run downloads language data (~20MB per language)
• Subsequent runs use cached data
• Works best with clear, high-contrast images
• For handwritten text, accuracy may vary

Language Data#

Language model files ( .traineddata.gz) are automatically downloaded on first use and stored in:

text

{baseDir}/scripts/tessdata/
- chi_sim.traineddata.gz (Simplified Chinese)
- eng.traineddata.gz (English)

To manually download or update language data:

bash

cd {baseDir}/scripts/tessdata
curl -O https://cdn.jsdelivr.net/npm/@tesseract.js-data/chi_sim/4.0.0_best_int/chi_sim.traineddata.gz
curl -O https://cdn.jsdelivr.net/npm/@tesseract.js-data/eng/4.0.0_best_int/eng.traineddata.gz