Tesseract vs Google Cloud Vision
| Feature | Tesseract.js | Google Cloud Vision |
|---|---|---|
| Cost | Free | Free tier, then paid |
| Offline | ✓ Yes | ✗ No |
| Setup | None | API key required |
| Speed | Medium | Fast |
| Accuracy | Good | Excellent |
| Rotated text | Poor | Excellent |
| Small text | Fair | Good |
| Languages | 100+ | 100+ |
Tesseract.js (Default)
Overview
Tesseract.js is an open-source OCR engine that runs entirely in your browser. No API key or internet connection required after initial load.
Strengths
- Free forever - No usage limits
- Privacy - All processing local
- Offline capable - Works without internet
- No setup - Works out of the box
Limitations
- Rotated text - Struggles with sideways spines
- Small text - May miss fine print
- Processing time - Slower than cloud APIs
Best For
- Privacy-conscious users
- Offline use
- High-contrast, well-lit photos
- Horizontally-oriented text
Tips for Tesseract
- Ensure good, even lighting
- Hold camera level (reduce rotation)
- Get close enough for large text
- Use high contrast (dark text on light background)
Google Cloud Vision
Overview
Google Cloud Vision is a cloud-based AI service with superior OCR capabilities. Requires a Google Cloud account and API key.
Strengths
- Excellent accuracy - Best-in-class OCR
- Rotated text - Handles any orientation
- Small text - Reads fine print
- Fast - Cloud processing is quick
- Document AI - Understands layout
Limitations
- Requires internet - No offline use
- API key needed - Setup required
- Usage costs - Free tier, then $1.50/1000 images
- Privacy - Photos sent to Google
Best For
- Difficult-to-read spines
- Large scanning sessions
- Books with vertical text
- Maximum accuracy needed
Setting Up Google Cloud Vision
-
Create Google Cloud Account
- Go to console.cloud.google.com
- Create a new project
-
Enable Vision API
- Go to APIs & Services
- Search for “Cloud Vision API”
- Click Enable
-
Create API Key
- Go to Credentials
- Create Credentials → API Key
- Copy the key
-
Add to BookSpineScanner
- Open BookSpineScanner settings
- Paste API key in “Google Cloud Vision API Key”
- Select “Google Cloud Vision” as OCR engine
Free Tier Limits
Google Cloud Vision offers:
- 1,000 free images per month
- Then $1.50 per 1,000 images
For most home libraries, the free tier is sufficient.
Choosing an Engine
Use Tesseract.js When:
- Scanning occasional books
- Privacy is important
- You need offline capability
- Books have clear, large spine text
- Cost is a concern
Use Google Cloud Vision When:
- Scanning large collections
- Many books have small/rotated text
- Accuracy is critical
- You have good internet
- Already using Google Cloud
Switching Engines
- Open BookSpineScanner
- Click Settings (gear icon)
- Under “OCR Engine”, select your choice
- If using Google Vision, enter your API key
- Save settings
The setting persists in your browser.
Language Support
Both engines support multiple languages:
Tesseract.js
Languages must be downloaded on first use:
- English (default)
- Spanish, French, German, etc.
- Download additional languages in settings
Google Cloud Vision
- Automatically detects language
- Supports 100+ languages
- No configuration needed
Performance tips
For Tesseract.js
- Reduce image size - Lower resolution is faster
- Crop to spines - Less area to process
- Preprocess - High contrast helps
For Google Cloud Vision
- Batch photos - Process multiple photos at once
- Monitor usage - Stay within the free tier
- Cache results - Avoid reprocessing