Seeing a small OCR accuracy bump

Ran 1,000 invoice pages through the latest Textract and Form Recognizer this morning and saw 98.4% vs 97.7% field-level accuracy — tiny, but it cuts about 6 corrections per 1,000 fields for us. Anyone have benchmarks on tables/line-items, especially mis-splits at 12+ columns?

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On 14‑column invoices I cut ‘mis-splits’ about 22% by post‑processing: k‑means on cell x‑centers to define 12–16 column bands, then snap to bands before reconciliation (Textract Tables or FR Layout both gained about 1.5–2 pts F1). Caveat: it can over‑merge skinny columns; on Form Recognizer, routing 12+ cols to Layout + this snapper beat the prebuilt for me — want a tiny script?

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Building on @OpsTheo, try header‑anchored banding: detect header tokens (“Qty”, “Unit Price”, etc.), RANSAC‑fit 12–16 vertical bands, then snap cells to those like bowling bumpers; this cut our mis‑splits about 28% on 13–15 col POs. Caveat: it needs decent header recall, so we fall back to x‑projection peaks when headers are missing. Do you see many headerless line‑item pages?

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We cut wrong column assignments about 18% on 12–15 column invoices by doing a post‑OCR constrained assignment: estimate per‑row column x‑anchors via robust regression with a minimum gap, then use a tiny ILP to map cells and merge over‑segmentation — kept columns from playing musical chairs. If headers are sparse we fall back to Microsoft’s Table Transformer (GitHub - microsoft/table-transformer: Table Transformer (TATR) is a deep learning model for extracting tables from unstructured documents (PDFs and images). This is also the official repository for the PubTables-1M dataset and GriTS evaluation metric.); do your vendors have reliable headers?

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That 98.4% vs 97.7% bump is real; the drift on wide tables drives me nuts, and we clawed back a bit by strip‑wise deskew/shear before column mapping on 12–16‑column layouts. Slice the page into 8–12 vertical stripes, fit local baselines from character boxes (OpenCV LSD/Hough), then shear each stripe so x stays stable across the row — dropped cross‑column bleed about 19% on 14‑column sets. @OpsTheo are you seeing lateral drift from curl/warp; if so this pass usually saves a couple more fixes per about 1k fields; ref: https://docs.opencv.org/4.x/d5/db5/tutorial_lsd.html.

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For ‘12+ columns’, normalize to 300 DPI, run horizontal RLSA, then Textract; fewer splits. Seen similar?

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And on ‘12+ columns’, a small win for us was stripping vertical ruling lines before OCR: detect thin verticals with a Hough pass, erase/inpaint, then feed the cleaned image to Textract/Form Recognizer. It cut mis-splits on wide invoices noticeably and shaved about 4–6 corrections per 1k fields, but only pays off when the source has heavy gridlines; on lightly ruled PDFs it’s negligible.

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