Preprocess a receipt image without erasing the signal
Apply a basic OpenCV preprocessing sequence to make receipt text easier to extract.
OCR is misreading a tilted, shadowed receipt photo because background clutter and uneven lighting obscure small printed digits. Preserve text signal: crop the document, normalize intensity, separate text from background, then verify characters remain legible. The common shortcut is to apply a harsh global threshold to the whole photo. It may look cleaner while erasing thin strokes in small numbers. Find the document region Detect the largest receipt-like contour and crop around it instead of sending the full table, hand, and background to OCR. Cropping removes visual clutter before text extraction and reduces the chance that OCR reads non-receipt objects.…
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