How to Highlight Precise Areas in a Scanned PDF with Acrobat
Question details
The user needs to highlight exact regions of an invoice or scanned document, but the highlighting tool selects large, incorrect areas.
- Product
- Adobe Acrobat
- Device & OS
- not provided
- Scenario
- Attempting to mark up specific sections of a scanned PDF where text recognition has failed or is inaccurate.
- Observed behavior
- Acrobat's text highlighter selects unexpected shapes or large portions of the page instead of the precise text the user wants to mark.
Ensure your scanned PDF is open in Adobe Acrobat and that you have located the specific area of the invoice or document you wish to highlight.
Use Free-Form Selection with the Ctrl Key
Bypass inaccurate text recognition by forcing Acrobat into free-form selection mode, allowing you to draw a highlight anywhere on the page.
When Acrobat's Optical Character Recognition (OCR) yields poor results, the standard text highlight tool snaps to incorrect, invisible text boundaries. By using a keyboard modifier, you can override this behavior and draw precise, rectangular highlights over any region.
Click on the 'Highlight text' tool icon located in the quick tools menu at the top of your Adobe Acrobat window.
Before attempting to click or select the area on the document, press and hold the 'Ctrl' key on your keyboard.
While holding the 'Ctrl' key, click and drag your mouse cursor over the exact region of the invoice you want to mark, then release the mouse button to apply the free-form highlight.
Improve Scan Quality and Re-run Text Recognition
If you frequently need to highlight actual text, improving the document's optical character recognition (OCR) will allow the highlighter to snap accurately.
Highlight Scanned PDFs Easily with WPS Office
WPS Office includes a versatile PDF editor equipped with a dedicated Area Highlight tool, allowing you to instantly mark up exact regions on scanned documents and invoices without fighting inaccurate text recognition.
- 1. Open Your PDF: Launch WPS Office and open your scanned document or invoice within the WPS PDF editor.
- 2. Navigate to the Comment Tab: Click on the 'Comment' tab located in the top navigation ribbon to access your markup and annotation tools.
- 3. Select Area Highlight: Click on the 'Area Highlight' tool from the menu. This tool is specifically designed to bypass text recognition and highlight specific geometric areas.
- 4. Draw Your Selection: Click and drag to draw a precise rectangle over the exact region you want to highlight, applying perfect color overlays instantly.
Frequently Asked Questions
Why does my PDF highlighter select large, unexpected shapes instead of text?
This typically occurs in scanned documents when the Optical Character Recognition (OCR) fails to accurately identify text boundaries. Because the software interprets the text as one large block or distorted shape, the highlighter snaps to these incorrect boundaries instead of individual words.
Can I highlight non-text areas or images in a PDF?
Yes. In most PDF editors, you can bypass text-snapping by using a free-form highlight shortcut (such as holding Ctrl while dragging in Acrobat) or by utilizing a dedicated 'Area Highlight' tool to draw a colored box over images, blank spaces, or unreadable text.
How can I get better text recognition results on scanned invoices?
To improve OCR accuracy, ensure your original scan is straight, has high contrast, and is scanned at a minimum resolution of 300 DPI. Using your PDF software's 'Enhance Scan' or image cleanup features before running the text recognition tool can significantly improve the accuracy of the selectable text.
