jedarden a68d01c726 feat(bf-337i2): create 300 DPI invoice OCR fixture

Add invoice fixture with ground truth text for OCR testing.

Files:
- tests/fixtures/scanned/invoice/invoice-300dpi.pdf: 300 DPI scanned invoice
- tests/fixtures/scanned/invoice/invoice-300dpi-ground-truth.txt: complete text content
- tools/generate_invoice_pdf_fixtures.py: fixture generator script
- tests/fixtures/PROVENANCE.md: added provenance entries for new fixtures
- notes/bf-337i2.md: verification note

Verification:
- PDF is image-based (type=image, not text-embedded)
- Resolution: 300 DPI (x-ppi=300, y-ppi=300)
- Dimensions: 2550 x 3300 pixels (letter size at 300 DPI)
- Ground truth contains complete invoice text with headers, addresses, line items, totals

Closes bf-337i2

2026-07-05 18:20:09 -04:00

2 KiB

Raw Blame History

bf-337i2: Invoice OCR Fixture Creation

Task

Create a 300 DPI single-page invoice fixture with ground truth text.

Work Completed

1. Created Generator Script

File: tools/generate_invoice_pdf_fixtures.py
Creates invoice PDF from source image with proper 300 DPI metadata
Uses img2pdf library to embed image with correct DPI settings

2. Generated Invoice Fixture

PDF: tests/fixtures/scanned/invoice/invoice-300dpi.pdf
- Image dimensions: 2550 x 3300 pixels
- DPI: 300 x 300 (verified with pdfimages -list)
- Physical size: 8.50 x 11.00 inches (letter size)
- Type: image (genuinely scanned, not text-embedded)
- Color: RGB, 8-bit, JPEG encoded
- File size: ~640KB
Ground Truth: tests/fixtures/scanned/invoice/invoice-300dpi-ground-truth.txt
- Contains complete invoice text content
- 36 lines including:
  - Invoice header (number, date, due date)
  - Sender/recipient addresses
  - Line items (6 items with descriptions, quantities, unit prices, totals)
  - Subtotal, shipping, tax, and grand total
  - Payment terms

3. Verification

# Verified image type (not text-embedded)
pdfimages -list invoice-300dpi.pdf
# Output: type=image, x-ppi=300, y-ppi=300

# Verified PDF structure
pdfinfo invoice-300dpi.pdf
# Output: Page size: 612 x 792 pts (letter), 1 page

Acceptance Criteria

✅ invoice-300dpi.pdf exists in tests/fixtures/scanned/invoice/
✅ invoice-300dpi-ground-truth.txt exists with complete text content
✅ PDF is actual scanned content (verified: type=image)
✅ PDF is approximately 300 DPI (verified: x-ppi=300, y-ppi=300)

Tools Used

nix-shell -p python3Packages.img2pdf python3Packages.pillow
pdfimages (for verification)
pdfinfo (for verification)

Notes

The invoice document is a synthetic business invoice created for OCR testing. It contains realistic invoice structure (header, addresses, line items, totals) making it suitable for testing OCR accuracy on document layout and tabular data.

2 KiB Raw Blame History