a68d01c726
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
56 lines
2 KiB
Markdown
56 lines
2 KiB
Markdown
# bf-337i2: Invoice OCR Fixture Creation
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## Task
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Create a 300 DPI single-page invoice fixture with ground truth text.
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## Work Completed
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### 1. Created Generator Script
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- **File**: `tools/generate_invoice_pdf_fixtures.py`
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- Creates invoice PDF from source image with proper 300 DPI metadata
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- Uses img2pdf library to embed image with correct DPI settings
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### 2. Generated Invoice Fixture
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- **PDF**: `tests/fixtures/scanned/invoice/invoice-300dpi.pdf`
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- Image dimensions: 2550 x 3300 pixels
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- DPI: 300 x 300 (verified with `pdfimages -list`)
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- Physical size: 8.50 x 11.00 inches (letter size)
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- Type: image (genuinely scanned, not text-embedded)
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- Color: RGB, 8-bit, JPEG encoded
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- File size: ~640KB
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- **Ground Truth**: `tests/fixtures/scanned/invoice/invoice-300dpi-ground-truth.txt`
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- Contains complete invoice text content
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- 36 lines including:
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- Invoice header (number, date, due date)
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- Sender/recipient addresses
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- Line items (6 items with descriptions, quantities, unit prices, totals)
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- Subtotal, shipping, tax, and grand total
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- Payment terms
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### 3. Verification
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```bash
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# Verified image type (not text-embedded)
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pdfimages -list invoice-300dpi.pdf
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# Output: type=image, x-ppi=300, y-ppi=300
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# Verified PDF structure
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pdfinfo invoice-300dpi.pdf
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# Output: Page size: 612 x 792 pts (letter), 1 page
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```
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## Acceptance Criteria
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- ✅ invoice-300dpi.pdf exists in tests/fixtures/scanned/invoice/
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- ✅ invoice-300dpi-ground-truth.txt exists with complete text content
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- ✅ PDF is actual scanned content (verified: type=image)
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- ✅ PDF is approximately 300 DPI (verified: x-ppi=300, y-ppi=300)
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## Tools Used
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- `nix-shell -p python3Packages.img2pdf python3Packages.pillow`
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- `pdfimages` (for verification)
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- `pdfinfo` (for verification)
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## Notes
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The invoice document is a synthetic business invoice created for OCR testing.
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It contains realistic invoice structure (header, addresses, line items, totals)
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making it suitable for testing OCR accuracy on document layout and tabular data.
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