What OCR does for scanned PDF files

The difference between a text image and searchable text, plus ways to improve recognition.

A scan is not automatically text

A scanned page may look clear to a person while a computer sees one large image. OCR recognizes character shapes and adds a searchable text layer, which is useful for archives, invoices and paper correspondence.

Accuracy starts before processing

Straighten pages, improve contrast and select the correct document language. Blur, shadows and cropped edges reduce recognition quality. Extremely high resolution is less important than complete, clearly shaped characters.

Human review still matters

Names, numbers, tables and decorative fonts are more error-prone. After OCR, search for critical values and compare them with the source image, especially before using extracted data in a contract or financial system.