Optical character recognition engines

The Java™ document viewer toolkit defines a pluggable interface to enable support for an optical character recognition (OCR) engine. An OCR engine is designed to recognize text from an image, which helps you do tasks such as copy, paste, and search with screen readers.

About this task

A sample OCR engine implementation is provided for the Nuance OmniPage Capture Software Development Kit (SDK). If you have a license for the Nuance OmniPage Capture SDK, you can use this sample OCR engine to enable the Java document viewer for OCR technology. For more information, see the Java class file com.ibm.mm.viewer.samples.ocr.OmnipageOCREngine.java in the OCR samples. You can also write your own OCR engine by extending the Java class CMBOCREngine. For more information, see the Application Programming Reference.

When you use a valid OCR engine, the following tools are available: ocr_doc, find, and select_text. These tools can be added to a viewer toolbar in an engine properties file. For example: 
OperationToolbar.tools=ocr_doc,select_text,find,separator,save_doc, ...

Procedure

To specify an OCR engine in the Java document viewer toolkit, set the following properties to indicate the class name and path of your OCR engine.
These properties can either be specified in an engine properties file, such as cmbviewerengine.properties, or specified programmatically:
  • OCRENGINE_CLASSNAME
  • OCRENGINE_exePath

Example

The following example demonstrates how to specify an OCR engine in an engine properties file:
OCRENGINE_CLASSNAME=com.ibm.mm.viewer.samples.ocr.OmnipageOCREngine
OCRENGINE_exePath=c:\cm8\windows\nativelib
The following example demonstrates how to specify an OCR engine programmatically:
Properties engineCMProperties = new Properties();
engineCMProperties.put("ENGINES","2");
engineCMProperties.put("ENGINE1_CLASSNAME",
"com.ibm.mm.viewer.CMBSnowboundEngine");
engineCMProperties.put("ENGINE2_CLASSNAME",
"com.ibm.mm.viewer.CMBOutsideInExportEngine");
engineCMProperties.put("OCRENGINE_CLASSNAME",
"com.ibm.mm.viewer.samples.ocr.OmnipageOCREngine");
engineCMProperties.put("OCRENGINE_exePath",
"c:\\cm8\\windows\\nativelib");

// Create document services.
docServices = new CMBStreamingDocServices(
new StreamingDocServicesCallbacks(), engineCMProperties);