When I pipeline scanned responses into topic models, model output repeatedly reflected OCR artifacts. Map the pattern:…
Open the scanned PDF in Adobe Acrobat.
Check if the document is an image-only PDF by attempting to select or search for text.
NoteOCR cannot recognize text if the PDF does not contain images or if the text is already selectable.
Go to Tools and select Recognize Text.
Click Recognize Text and choose In This File.
Review the OCR output for errors or missed text by scrolling through the document.
If OCR accuracy is poor, check the scan quality: ensure the document is at least 300 dpi, not skewed, and has high contrast.
Best practiceLow-resolution, blurry, or skewed scans are the most common causes of OCR failure.
Rescan the original document at 300 dpi or higher, using RGB mode for discolored or older pages.
Best practiceFor best results, avoid scanning with excessive brightness and ensure pages are flat and unmarked.
Repeat the OCR process on the improved scan.
Manually correct any remaining OCR errors by clicking on suspect words to edit and accept corrections directly.
NoteYou can click on suspect words to edit and accept corrections directly.
Save the corrected PDF.
If OCR still fails, try rescanning your document at a higher resolution and check for skewed or blurry pages before running OCR again.
This runs in the Acrobat app - there is no separate API for this task.
OCR fails with 'page contains renderable text' because the page already has actual, selectable text. Acrobat's OCR feature is designed only for image-based pages where the text is part of a picture. It cannot be used on pages that already contain real text that a computer can read.
For the best OCR accuracy, you should scan your documents at 300 dpi (dots per inch). This resolution provides enough detail for Acrobat to correctly identify characters. While 72 dpi is the minimum, 300 dpi gives much better results for text recognition.
If your scan is blurry, OCR might not work well. OCR relies on clear images of text to accurately recognize characters. A blurry scan can lead to many errors in the recognized text, making it less useful. It's best to ensure your scan is clear and at a high DPI, like 300, for good OCR results.
Yes, you can automate making many scanned PDFs searchable. Adobe provides a PDF Services API, specifically the 'OCR PDF' operation. This allows developers to send image-based PDFs to a cloud service that converts the image text into a searchable layer, which is perfect for bulk processing and integration into other systems.