Files
pdf_signature_extraction/SESSION_CHECKLIST.md
gbanyan 52612e14ba Add hybrid signature extraction with name-based verification
Implement VLM name extraction + CV detection hybrid approach to
replace unreliable VLM coordinate system with name-based verification.

Key Features:
- VLM extracts signature names (周寶蓮, 魏興海, etc.)
- CV or PDF text layer detects regions
- VLM verifies each region against expected names
- Signatures saved with person names: signature_周寶蓮.png
- Duplicate prevention and rejection handling

Test Results:
- 5 PDF pages tested
- 7/10 signatures extracted (70% recall)
- 100% precision (no false positives)
- No blank regions extracted (previous issue resolved)

Files:
- extract_pages_from_csv.py: Extract pages from CSV (tested: 100 files)
- extract_signatures_hybrid.py: Hybrid extraction (current working solution)
- extract_handwriting.py: CV-only approach (component)
- extract_signatures_vlm.py: Deprecated VLM coordinate approach
- PROJECT_DOCUMENTATION.md: Complete project history and results
- SESSION_INIT.md: Session handoff documentation
- SESSION_CHECKLIST.md: Status checklist
- NEW_SESSION_PROMPT.txt: Template for next session
- HOW_TO_CONTINUE.txt: Visual handoff guide
- COMMIT_SUMMARY.md: Commit preparation guide
- README.md: Quick start guide
- README_page_extraction.md: Page extraction docs
- README_hybrid_extraction.md: Hybrid approach docs
- .gitignore: Exclude diagnostic scripts and outputs

Known Limitations:
- 30% of signatures missed due to conservative CV parameters
- Text layer method untested (all test PDFs are scanned images)
- Performance: ~24 seconds per PDF

Next Steps:
- Tune CV parameters for higher recall
- Test with larger dataset (100+ files)
- Process full dataset (86,073 files)

🤖 Generated with Claude Code
2025-10-26 23:39:52 +08:00

5.5 KiB

Session Handoff Checklist ✓

Before You Exit This Session

  • All documentation written
  • Test results recorded (7/10 signatures, 70% recall)
  • Session initialization files created
  • .gitignore configured
  • Commit guide prepared
  • Git commit performed (waiting for user approval)

Files Created for Next Session

Essential Files

  • SESSION_INIT.md - Read this first in next session
  • NEW_SESSION_PROMPT.txt - Copy-paste prompt template
  • PROJECT_DOCUMENTATION.md - Complete 24KB history
  • HOW_TO_CONTINUE.txt - Visual guide

Supporting Files

  • README.md - Quick start guide
  • COMMIT_SUMMARY.md - Git instructions
  • README_page_extraction.md - Page extraction docs
  • README_hybrid_extraction.md - Signature extraction docs
  • .gitignore - Configured properly

Working Scripts

  • extract_pages_from_csv.py - Tested (100 files)
  • extract_signatures_hybrid.py - Tested (5 files, 70% recall)
  • extract_handwriting.py - Component script

What's Working

Component Status Details
Page extraction Working 100 files tested
VLM name extraction Working 100% accurate on 5 files
CV detection ⚠️ Conservative Finds 70% of signatures
VLM verification Working 100% precision, no false positives
Overall system Working 70% recall, 100% precision

What's Not Working / Unknown ⚠️

Issue Status Next Steps
Missing 30% signatures Known Tune CV parameters
Text layer method Untested Need PDFs with text
Large-scale performance Unknown Test with 100+ files
Full dataset (86K) Unknown Estimate time & optimize

Critical Context to Remember 🧠

  1. VLM coordinates are unreliable (32% offset on test file)

    • Don't use VLM for location detection
    • Use VLM for name extraction only
  2. Name-based approach is the solution

    • VLM extracts names ✓
    • CV finds locations ✓
    • VLM verifies regions ✓
  3. Test file with coordinate issue:

    • 201301_2458_AI1_page4.pdf
    • VLM found 2 names but coordinates pointed to blank areas
    • Actual signatures at 26% (reported as 58% and 68%)

To Start Next Session

cat /Volumes/NV2/pdf_recognize/NEW_SESSION_PROMPT.txt
# Copy output and paste to new Claude Code session

Manual Method

Tell Claude:

"I'm continuing the PDF signature extraction project at /Volumes/NV2/pdf_recognize/. Please read SESSION_INIT.md and PROJECT_DOCUMENTATION.md to understand the current state. I want to [choose option from SESSION_INIT.md]."

Quick Commands Reference

View Documentation

less /Volumes/NV2/pdf_recognize/SESSION_INIT.md
less /Volumes/NV2/pdf_recognize/PROJECT_DOCUMENTATION.md

Run Scripts

cd /Volumes/NV2/pdf_recognize
source venv/bin/activate
python extract_signatures_hybrid.py  # Main script

Check Results

ls -lh /Volumes/NV2/PDF-Processing/signature-image-output/signatures/*.png

View Session Handoff

cat /Volumes/NV2/pdf_recognize/HOW_TO_CONTINUE.txt

What Can Be Improved (Future Work)

Priority 1: Increase Recall

  • Current: 70%
  • Target: 90%+
  • Method: Tune CV parameters in lines 178-214 of extract_signatures_hybrid.py

Priority 2: Scale Testing

  • Current: 5 files tested
  • Next: 100 files
  • Future: 86,073 files (full dataset)

Priority 3: Optimization

  • Current: ~24 seconds per PDF
  • Consider: Parallel processing, batch VLM calls

Priority 4: Text Layer Testing

  • Current: Untested (all PDFs are scanned)
  • Need: Find PDFs with searchable text layer

Verification Steps

Before next session, verify files exist:

cd /Volumes/NV2/pdf_recognize

# Check essential docs
ls -lh SESSION_INIT.md PROJECT_DOCUMENTATION.md NEW_SESSION_PROMPT.txt

# Check working scripts
ls -lh extract_pages_from_csv.py extract_signatures_hybrid.py

# Check test results
ls /Volumes/NV2/PDF-Processing/signature-image-output/signatures/*.png | wc -l
# Should show: 7 (the 7 verified signatures)

Known Good State

Environment

Test Data

  • 5 PDFs processed
  • 7 signatures extracted
  • All verified (100% precision)
  • 3 signatures missed (70% recall)

Output Files

201301_1324_AI1_page3_signature_張志銘.png (33 KB)
201301_1324_AI1_page3_signature_楊智惠.png (37 KB)
201301_2061_AI1_page5_signature_廖阿甚.png (87 KB)
201301_2458_AI1_page4_signature_周寶蓮.png (230 KB)
201301_2923_AI1_page3_signature_黄瑞展.png (184 KB)
201301_3189_AI1_page3_signature_黄益辉.png (24 KB)
201301_3189_AI1_page3_signature_黄辉.png (84 KB)

Git Status (Pre-Commit)

Files staged for commit:

  • extract_pages_from_csv.py
  • extract_signatures_hybrid.py
  • extract_handwriting.py
  • README.md
  • PROJECT_DOCUMENTATION.md
  • README_page_extraction.md
  • README_hybrid_extraction.md
  • .gitignore

Waiting for: User to review docs and approve commit

Session Health Check ✓

  • All scripts working
  • Test results documented
  • Issues identified and recorded
  • Next steps defined
  • Session continuity files created
  • Git commit prepared

Status: Ready for handoff


Last Updated: October 26, 2025 Session End: Ready for next session Next Action: User reviews docs → Git commit → Continue work