How to Use OCR For a PDF

Optical Character Recognition, or OCR for short, is the process a computer uses to recognize letters, numbers, and special characters in pictures. Even though you may be able to read the content in a PDF file, a computer considers the writing to be a picture unless OCR has been applied. You can test if a PDF has been OCRed by trying to highlight a word in the file with your cursor; if you can't pick out a word, the file needs OCR. Luckily, many software tools can apply OCR to a PDF file in seconds.

Instructions

Free Online OCR

1. Visit the Free Online OCR website.

2. Click the "Choose File" button.

3. Select the language in the original PDF (for example, English) from the drop-down menu.

4. Type the two words you see in the box. This is known as a CAPTCHA and prevents automated computer bots from using the service.

5. Click the "Send File" button.

6. All the text from the original PDF is displayed in a text box on the screen. To save the text, highlight it with your mouse, press "Ctrl+C" (for Copy), open a new document in your word processing program (for example, Word or Notepad), and press "Ctrl+V" (for Paste). Save the file by pressing "Ctrl+S."

Adobe Acrobat

1. Download and install Adobe Acrobat.

2. Choose "Open" from the "File" menu in Adobe Acrobat. Double-click on your original PDF file to open it.

3. Click "Document" in the file menu. Choose "OCR Text Recognition" then "Recognize Text Using OCR."

4. Choose "Save" from the "File" menu to save your updated PDF.

OmniPage Pro

1. Download and install OmniPage Pro.

2. Choose "1-2-3" from the first drop-down list.

3. Choose "Load Files" from the second drop-down list. Click the button right above it.

4. Locate your PDF and double-click on it.

5. Choose "Automatic" from the third drop-down list. Click the button right above it to perform OCR on your PDF.

6. Choose "Save to File" from the fourth drop-down list. Click the button right above it to save your newly-OCRed PDF.

Tips & Warnings

• For best results, start with a PDF that has black text on a white background and uses a standard font (for example, Arial or Times New Roman) in size 12 or greater.

References

• Oregon Health & Science University: Computer Science: 2.3 OCR: Print
• Pacific Lutheran University: Basic Scanning: Optical Character Recognition (OCR)
• Princeton University: Academic Services: Free Online OCR
• Princeton University: East Asian Library: Using the Scanner at the Project Workstation in Jones Hall
• Rice University: Fondren Library: OCR (Text Scanning)

Resources

• Free Online OCR
• Adobe: Adobe Acrobat Reader
• Nuance Document Imaging Solutions: OmniPage Suite OCR