HOW TO: Accessing and Modifying NativeOcrZones

#1 Posted : Friday, January 25, 2019 4:22:53 PM(UTC)

Nick

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The LEADTOOLS SDK uses OcrZones to define regions of interest. Behind the scenes, they are converted into NativeOcrZone structures specific to the engine being used. It is not possible to directly add a NativeOcrZone. However, generated NativeOcrZones can be extracted and modified.

Here's a code snippet that shows how to access a NativeOcrZone, modify one of its properties, and re-insert it back into the collection:

Code:


         using (IOcrEngine engine = OcrEngineManager.CreateEngine(OcrEngineType.LEAD, false))
         {
            engine.Startup(null, null, null, null);

            IOcrPage page = engine.CreatePage(inputImage, OcrImageSharingMode.None);

            // insert a new zone
            page.Zones.Add(new OcrZone() { Bounds = new LeadRect(0, 0, 100, 100)});

            // extract the NativeOcrZone at index 0 (the OcrZone we just added)
            NativeOcrZone nativeZone = engine.ZoneManager.GetNativeZone(page, 0);

            // change one of its properties
            nativeZone.RecognitionModule = NativeOcrZoneRecognitionModule.DotMatrix;

            // insert the zone back into its original index
            engine.ZoneManager.SetNativeZone(page, 0, nativeZone);


            page.Recognize(null);
            engine.Shutdown();
         }

Here's our documentation links for the GetNativeZone() and SetNativeZone() methods.
https://www.leadtools.com/help/leadtools/v20/dh/fo/iocrzonemanager-getnativezone.html
https://www.leadtools.com/help/leadtools/v20/dh/fo/iocrzonemanager-setnativezone.html

Do note that for a vast majority of OCR operations using the OcrZone structure is sufficient and accessing the NativeOcrZones is not necessary.

However, this demonstrates a way to accommodate edge cases where it's necessary to access lower-level properties that aren't immediately exposed, such as the NativeOcrZoneRecognitionModule as detailed. For more information, see our overview on Recognition Modules:
https://www.leadtools.com/help/leadtools/v20/dh/to/an-overview-of-ocr-recognition-modules-for-the-leadtools-ocr-module-omnipage-engine.html

Nick Crook
Developer Support Engineer
LEAD Technologies, Inc.


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HOW TO: Accessing and Modifying NativeOcrZones