gbanyan cb38d413ad Paper A v13 rev9: sensitivity surface + honesty fixes (GPT-5.5 hostile review)
Pre-emptively address the three residual points from a hostile GPT-5.5
reviewer pass that rev8 had not fully closed (the rest of that review
matched the already-applied fusion revision):

- Sensitivity surface (Major 5): new Figure 6 maps the deployed rule over
  the full (cosine cut x dHash cut) plane - clean-group flag rate and the
  Firm A-minus-B/C/D contrast. Shows no cliff at (0.95, dHash<=5), contrast
  >45pp across a broad region (58pp at 0.97/dHash<=3), and that extending to
  the MC bound (dHash<=15) halves the contrast - so the thresholds are not
  cherry-picked and the weaker MC band is shown, not hidden. Reproducible
  via make_fig6_sensitivity.py (DB columns only).

- Soften "reuse-dominated" (Major 1): the assertion that Firm A "is" a
  reuse-dominated population now reads "behaves in the screen as," explicitly
  resting on interviews + byte-identity rather than per-signature ground
  truth; two other uses made conditional/generic.

- Shared-pipeline contamination of ICCR (Major 2): Sec III-E now names the
  shared within-firm imaging pipeline (scanners, PDF assembly, red-stamp
  removal) as a channel that can lift the inter-CPA rate above true chance,
  distinct from "shared template," supported by the Sec V-B pipeline audit;
  bias direction (higher floor) keeps the Firm-A contrast conservative.

rev9 docx rebuilt (6 figures embedded).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qn59FdF9JMyfFg3sjcUNNG
2026-06-23 14:59:55 +08:00

PDF Signature Extraction System

Automated extraction of handwritten Chinese signatures from PDF documents using hybrid VLM + Computer Vision approach.

Quick Start

Step 1: Extract Pages from CSV

cd /Volumes/NV2/pdf_recognize
source venv/bin/activate
python extract_pages_from_csv.py

Step 2: Extract Signatures

python extract_signatures_hybrid.py

Documentation

Current Performance

Test Dataset: 5 PDF pages

  • Signatures expected: 10
  • Signatures found: 7
  • Precision: 100% (no false positives)
  • Recall: 70%

Key Features

Hybrid Approach: VLM name extraction + CV detection + VLM verification Name-Based: Signatures saved as signature_周寶蓮.png No False Positives: Name-specific verification filters out dates, text, stamps Duplicate Prevention: Only one signature per person Handles Both: PDFs with/without text layer

File Structure

extract_pages_from_csv.py          # Step 1: Extract pages
extract_signatures_hybrid.py       # Step 2: Extract signatures (CURRENT)
README.md                          # This file
PROJECT_DOCUMENTATION.md           # Complete documentation
README_page_extraction.md          # Page extraction guide
README_hybrid_extraction.md        # Signature extraction guide

Requirements

Data

  • Input: /Volumes/NV2/PDF-Processing/master_signatures.csv (86,073 rows)
  • PDFs: /Volumes/NV2/PDF-Processing/total-pdf/batch_*/
  • Output: /Volumes/NV2/PDF-Processing/signature-image-output/

Status

Page extraction: Tested with 100 files, working Signature extraction: Tested with 5 files, 70% recall, 100% precision Large-scale testing: Pending Full dataset (86K files): Pending

See PROJECT_DOCUMENTATION.md for complete details.

S
Description
Automated extraction of handwritten Chinese signatures from PDF documents using hybrid VLM + Computer Vision approach. 70% recall, 100% precision.
Readme 14 MiB
Languages
Python 100%