8037e67e82
- Add borderless detection benchmark to table_detection.rs - Verify < 10 ms performance requirement (achieved 1.56 ms for 5040 positions) - Confirm all unit tests pass for borderless detection - Borderless detection implementation already existed in detector.rs Acceptance criteria: - PASS: 3x3 borderless table detected via alignment heuristic - PASS: paragraph rejected; one-row pseudo-table rejected - PASS: vertical-gap test; 3-row 3-column borderless table accepted - PASS: Public API TableDetector::detect_borderless() exists - PASS: Performance < 10 ms on 5000-span page (measured 1.56 ms) Co-Authored-By: Claude Code <noreply@anthropic.com>
70 lines
3.5 KiB
Markdown
70 lines
3.5 KiB
Markdown
# Verification Note: pdftract-3nwz (Borderless Table Detection)
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## Summary
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Implemented borderless table detection using x0-aligned span heuristic. The implementation was already present in the codebase and all tests pass.
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## Changes Made
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1. Added benchmark for borderless detection to verify performance
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2. Verified all acceptance criteria are met
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## Acceptance Criteria Status
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### PASS
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- **Critical test**: 3x3 borderless table detected via alignment heuristic
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- `test_detect_borderless_3x3_table_accepted` passes
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- **Unit test - paragraph rejected**: Single-column text is rejected
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- `test_detect_borderless_paragraph_rejected` passes
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- **Unit test - one-row pseudo-table rejected**: Single row with multiple columns rejected
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- `test_detect_borderless_one_row_pseudo_table_rejected` passes
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- **Unit test - 3-row 3-column borderless table accepted**: Core table detection works
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- `test_detect_borderless_3x3_table_accepted` passes
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- **Unit test - vertical-gap test**: Two separate tables with >100 pt gap detected separately
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- `test_detect_borderless_vertical_gap_test` passes
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- **Public API**: `TableDetector::detect_borderless(&PageContext) -> Vec<GridCandidate>` exists
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- **Performance**: 1.56 ms for 5040 text positions (well below 10 ms requirement)
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## Implementation Details
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The borderless detector in `crates/pdftract-core/src/table/detector.rs`:
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- Collects text positions from content stream (Tm, Td, TD, T*, Tj, TJ, ', " operators)
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- Groups by x0 positions within 2.0 pt tolerance using clustering
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- Finds column candidates (3+ spans at same x0 on different y positions)
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- Finds row candidates (y positions where >= 2 column candidates have spans)
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- Validates: 3+ rows AND 3+ columns, contiguous y range, no gap > 100 pt
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- Constructs GridCandidate with empty segments (no ruling lines)
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- Rejects single-column paragraph reflow patterns
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## Test Results
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```bash
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cargo test -p pdftract-core --lib table::detector::tests::test_detect_borderless
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# running 6 tests
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# test table::detector::tests::test_detect_borderless_empty_content ... ok
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# test table::detector::tests::test_detect_borderless_no_text_block ... ok
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# test table::detector::tests::test_detect_borderless_3x3_table_accepted ... ok
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# test table::detector::tests::test_detect_borderless_one_row_pseudo_table_rejected ... ok
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# test table::detector::tests::test_detect_borderless_paragraph_rejected ... ok
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# test table::detector::tests::test_detect_borderless_vertical_gap_test ... ok
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# test result: ok. 6 passed; 0 failed; 0 ignored; 0 measured
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```
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## Benchmark Results
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```
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borderless_detection/text_positions/5040
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time: [1.5457 ms 1.5595 ms 1.5755 ms]
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```
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Performance target: < 10 ms on 5000-span page
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Actual: ~1.56 ms (well within requirement)
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## Files Modified
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- `crates/pdftract-core/benches/table_detection.rs`: Added borderless detection benchmark
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## Files Reviewed (no changes needed)
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- `crates/pdftract-core/src/table/detector.rs`: Borderless detection already implemented
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- `crates/pdftract-core/src/table/mod.rs`: Public API exported
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- `crates/pdftract-core/src/lib.rs`: Re-exports for public API
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## Integration Notes
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Per task description, borderless detection should run only when line-based detection (7.2.1) returns no GridCandidate covering a region. This is a usage pattern for the caller, not enforced within the detector itself. The detector provides both methods independently:
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- `TableDetector::detect_line_based()` - for bordered tables
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- `TableDetector::detect_borderless()` - for borderless tables
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Callers can orchestrate the fallback logic as needed.
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