Pre-processing: deskew and denoise
Before OCR, straighten rotated pages and remove scan artifacts. Even a 2-degree skew can cause line-break errors in the extracted text. Most scan artifacts (speckles, shadow bands) confuse character recognition and produce garbage glyphs in the output.
OCR with layout awareness
Use an OCR engine that preserves spatial relationships between text blocks. Multi-column layouts, sidebars, and footnotes need positional context to be reconstructed correctly. MarkItDown Online layout-aware parser handles common two-column formats automatically.
Post-conversion quality gates
After conversion, check heading hierarchy, verify that tables have consistent column counts, and confirm no section is truncated. Scanned documents with low DPI or handwritten annotations will always need manual review. Budget 2 minutes per page for quality checking on critical documents. MarkItDown Online: https://getmarkitdown.com — sapsap@qq.com.