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NativeOcrZone Structure


Represents a native zone rectangular area on a page containing a feature of interest to the user.

public struct NativeOcrZone 
Public Structure NativeOcrZone  
   Inherits System.ValueType 
public class NativeOcrZone 
public value class NativeOcrZone : public System.ValueType  


Used with engine-specific zones. For more information, refer to IOcrZoneManager.GetNativeZone and IOcrZoneManager.SetNativeZone.

The NativeOcrZone structure contains all the necessary information for describing a zone. A zone is a rectangular area on an image containing a feature of interest to the user. The image data covered by each zone is handled and processed (typically recognized) separately.

Zones can be divided into two basic categories: whether a zone is to be recognized or whether it should be treated as graphic. Zones containing text information can be considered to be either of the flowing type or of a table type. This basic classification of zones helps the OCR engine handle text information correctly.

Zones are always associated with a filling method (NativeOcrZoneFillMethod) and one of the available recognition modules (NativeOcrZoneRecognitionModule). These determine which recognition algorithm will be applied to the zone during its processing.

Use the CharacterFilters property to modify the set of valid characters for recognition of the zone. Specifying the character set correctly is a recognition accuracy issue.

Other members of the zone structure specify how the checking subsystem will function for the particular zone.

Construct the zones of a page automatically using IOcrPage.AutoZone. You must call this method and finish any modification you might have to the zones before calling IOcrPage.Recognize.

Do not modify the NativeOcrZone.Id property. When adding zones, leave this value to the default of 0.

The NativeOcrZone.ZoneType property of the updating zone should be one of the following: NativeOcrZoneType.Text, NativeOcrZoneType.Table or NativeOcrZoneType.Graphics.

The preferred method of updating a zone is as illustrated in the code snippet above, first get the zone of interest, update it and set it back into the collection.

It is the developers responsibility to specify a valid recognition module-filling method pair. Otherwise any incorrectly set zone will have no recognition result. For more information, refer to An Overview of OCR Recognition Modules.

LEADTOOLS OCR .NET also supports OMR (Optical Mark Recognition) in all the engines. For more information, refer to Using OMR in LEADTOOLS .NET OCR.


For an example, refer to IOcrPage.AutoZone.


Target Platforms

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