egg/OCR

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egg 940a406dce chore: backup before code cleanup

Backup commit before executing remove-unused-code proposal.
This includes all pending changes and new features.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

2025-12-11 11:55:39 +08:00

2.1 KiB

Raw Blame History

Change: Fix Table Column Alignment with Header-Anchor Correction

Why

PP-Structure's table structure recognition frequently outputs cells with incorrect column indices, causing "column shift" where content appears in the wrong column. This happens because:

Semantic over Geometric: The model infers row/col from semantic patterns rather than physical coordinates
Vertical text fragmentation: Chinese vertical text (e.g., "报价内容") gets split into fragments
Missing left boundary: When table's left border is unclear, cells shift left incorrectly

The result: A cell with X-coordinate 213 gets assigned to column 0 (range 96-162) instead of column 1 (range 204-313).

What Changes

Add Header-Anchor Alignment: Use the first row (header) X-coordinates as column reference points
Add Coordinate-Based Column Correction: Validate and correct cell column assignments based on X-coordinate overlap with header columns
Add Vertical Fragment Merging: Detect and merge vertically stacked narrow text blocks that represent vertical text
Add Configuration Options: Enable/disable correction features independently

Impact

Affected specs: document-processing
Affected code:
- backend/app/services/table_column_corrector.py (new)
- backend/app/services/pdf_generator_service.py
- backend/app/core/config.py

Problem Analysis

Example: scan.pdf Table 7

Raw PP-Structure Output:

Row 5: "3、適應產品..." at X=213
       Model says: col=0

Header Row 0:
  - Column 0 (序號): X range [96, 162]
  - Column 1 (產品名稱): X range [204, 313]

Problem: X=213 is far outside column 0's range (max 162), but perfectly within column 1's range (starts at 204).

Solution: Force-correct col=0 → col=1 based on X-coordinate alignment with header.

Vertical Text Issue

Raw OCR:

Block A: "报价内" at X≈100, Y=[100, 200]
Block B: "容--"   at X≈102, Y=[200, 300]

Problem: These should be one cell spanning multiple rows, but appear as separate fragments.

Solution: Merge vertically aligned narrow blocks before structure recognition.

2.1 KiB Raw Blame History