Why does a document scan become blurry?
Blur usually comes from camera movement, focus on the wrong surface, insufficient light, glare, or aggressive cropping of a small region. More pixels do not fix motion blur. Stabilize the phone, add diffuse light, keep the document flat, and inspect the smallest text before discarding the paper.
Why can automatic edges be wrong?
Edge detection looks for high-contrast rectangles. A box, tabletop seam, nearby sheet, or strong shadow can appear more document-like than the intended page. Use a plain contrasting background and leave a clear border around the page. Always review the crop after capture.
Does OCR preserve the original layout?
Not always. OCR converts visual text into a reading order, so tables, vertical labels, columns, and decorative layouts can be rearranged. Treat the original page as the source of truth and verify extracted totals, dates, names, and identifiers.
Checklist reviewed July 27, 2026.