How to Improve OCR Accuracy for Scanned Documents

Aim for an effective resolution near 300 DPI for ordinary printed text. Tiny text may need more detail, while extreme resolution increases processing time without restoring detail that was never captured.

Flatten page curvature, avoid shadows across text and keep all character edges inside the image. A phone photo can work, but perspective distortion and uneven lighting make layout recognition harder.

Rotate and deskew before OCR. Improve contrast carefully: aggressive thresholding can erase punctuation or join nearby characters. Select the actual document language rather than assuming English.

For mixed scripts, test a representative page before processing a long document. More language models can increase ambiguity and processing cost.

• Test one difficult page first.
• Retain the original scan.
• Avoid repeated lossy image saves.
• Use table extraction for structured grids rather than plain-text OCR.

Do not judge accuracy only by reading a paragraph. Search for names, dates, decimal values, account numbers and headings that drive the next workflow.

A confidence score can direct attention, but manual comparison with the image remains necessary for important records.