| Advanced | 
 Specific implementation that uses the OmniPage OCR. 
 | 
| OCR | 
 This OCR engine is capable of recognizing characters (letter and numbers)
 accurately 
 | 
| OCRManager | 
 Manager class used to handle different OCR engines taken by the OCR
 extension point. 
 | 
| OCRPlugin | 
 OCR module plugin class. 
 | 
| OCRServiceImpl | 
 Implementation of the SettingService 
 | 
| OCRWebService | 
 Specific implementation that uses the online OCR Web Services:
 http://www.ocrwebservice.com. 
 | 
| PDFImageExtractor | 
 This utility class allows the extraction of raster images from a PDF document 
 | 
| PowerPDF | 
 Specific implementation that uses the Nuance Power PDF Advanced. 
 | 
| Tesseract | 
 Specific implementation that uses the Tesseract OCR. 
 |