IMPORTANT: The following discussion is for the LEADTOOLS Plus, Professional and Arabic engines only. The LEADTOOLS Advantage engine supports multi-threading and x64 platform natively and does not require the use of a "thunk server".
Some of the OCR engines supported by LEAD were designed to work in the following environment:
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32-bit process
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Single-threaded application
LEAD developed the LEADTOOLS OCR Thunk Server framework to work around these restrictions and enable the OCR engines to work in following environments:
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Multi-threaded 32-bit applications
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Link from a 64-bit process
The LEADTOOLS OCR Thunk Server framework works in the background to isolate the OCR engine in a separate process and marshal the various method calls and data back and forth between the engine and your application. To use the LEADTOOLS OCR Thunk Server in your .NET application, all you have to do is pass true to the useThunkServer parameter to the OcrEngineManager.CreateEngine method. The rest of your application code will remain unaffected. For an in depth discussion on when to use the Thunk Server and best practices for developing robust, multi-threaded server applications, refer to Multi-Threading with LEADTOOLS OCR.
Distribution Files
Additional files need to be included in distribution files for your application if you chose to use the LEADTOOLS OCR Thunk Server framework.
If your application is based on the LEADTOOLS .NET class library (Leadtools.Forms.Ocr), then you must distribute the following files as part of your application:
| File | Description |
|---|---|
| LtThunkServer.exe |
COM+ Thunk Server |
| LtDocthunku.dll |
Helper for the LEADTOOLS OCR Plus Engine |
| LtDocthunk2u.dll |
Helper for the LEADTOOLS OCR Professional Engine |
| LtDocthunkaru.dll |
Helper for the LEADTOOLS OCR Arabic Engine |
If your application is based on the LEADTOOLS CDLL library (Ltdoc and Ltdoc2), then you must distribute the above plus the following as part of the distribution files of your application:
| File | Description |
|---|---|
| LtThunkutlu.dll |
32 bit helper DLL for the LEADTOOLS CDLL framework |
| LtThunkutlx.dll |
64 bit helper DLL for the LEADTOOLS CDLL framework |
Deploying the LEADTOOLS OCR Thunk Server
The LEADTOOLS OCR Thunk Server is based on COM+ technology. You should register the server as part of the setup procedure for your application. Perform the following steps to register the LEADTOOLS OCR Thunk Server that ships with the LEADTOOLS .NET Class Library:
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Run the Windows Command prompt with Administrator privileges
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2. Run the following command:
[LEADTOOLS Installation Folder]"\Bin\Common\Ocr\LtThunkServer.exe" /regserver
These exact steps are used by the LEADTOOLS Installation program during setup. Your application should perform something similar to the above as part of its setup procedure.