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IOcrPage Interface
See Also  Members   Example
Leadtools.Forms.Ocr Namespace : IOcrPage Interface



Defines an image page in an OCR document.

Syntax

Visual Basic (Declaration) 
Public Interface IOcrPage
Visual Basic (Usage)Copy Code
Dim instance As IOcrPage
C# 
public interface IOcrPage
C++/CLI 
public interface class IOcrPage

Example

This example creates an OCR document and adds a page to it, displays various information about the page and then saves it as PDF file.

Visual BasicCopy Code
Public Sub OcrPageExample()
   ' Unlock the support needed for LEADTOOLS Plus OCR engine
   RasterSupport.Unlock(RasterSupportType.Document, "Replace with your own key here")
   RasterSupport.Unlock(RasterSupportType.OcrPlus, "Replace with your own key here")
   RasterSupport.Unlock(RasterSupportType.OcrPlusPdfLeadOutput, "Replace with your own key here")
   Dim tifFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.tif"
   Dim pdfFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.pdf"

   ' Create an instance of the engine
   Using ocrEngine As IOcrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Plus, False)
      ' Start the engine using default parameters
      ocrEngine.Startup(Nothing, Nothing, Nothing, Nothing)

      ' Create an OCR document
      Using ocrDocument As IOcrDocument = ocrEngine.DocumentManager.CreateDocument()
         ' Add this image to the document
         Dim ocrPage As IOcrPage = ocrDocument.Pages.AddPage(tifFileName, Nothing)

         ' Auto-recognize the zones in the page
         ocrPage.AutoZone(Nothing)

         ' Show its information
         Console.WriteLine("Size: {0} by {1} pixels", ocrPage.Width, ocrPage.Height)
         Console.WriteLine("Resolution: {0} by {1} dots/inch", ocrPage.DpiX, ocrPage.DpiX)
         Console.WriteLine("Bits/Pixel: {0}, Bytes/Line: {1}", ocrPage.BitsPerPixel, ocrPage.BytesPerLine)

         Dim palette() As Byte = ocrPage.GetPalette()
         Dim paletteEntries As Integer
         If (Not palette Is Nothing) Then
            paletteEntries = palette.Length \ 3
         Else
            paletteEntries = 0
         End If

         Console.WriteLine("Number of entries in the palette: {0}", paletteEntries)
         Console.WriteLine("Original format of this page: {0}", ocrPage.OriginalFormat)
         Console.WriteLine("Has this page been recognized? : {0}", ocrPage.IsRecognized)
         ShowZonesInfo(ocrPage)

         ' Recognize it and save it as PDF
         ocrPage.Recognize(Nothing)
         ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, Nothing)
      End Using

      ' Shutdown the engine
      ' Note: calling Dispose will also automatically shutdown the engine if it has been started
      ocrEngine.Shutdown()
   End Using
End Sub

Private Sub ShowZonesInfo(ByVal ocrPage As IOcrPage)
   Console.WriteLine("Zones:")
   For Each ocrZone As OcrZone In ocrPage.Zones
      Dim index As Integer = ocrPage.Zones.IndexOf(ocrZone)
      Console.WriteLine("Zone index: {0}", index)
      Console.WriteLine(" Id {0}", ocrZone.Id)
      Console.WriteLine(" Bounds {0}", ocrZone.Bounds)
      Console.WriteLine(" ZoneType {0}", ocrZone.ZoneType)
      Console.WriteLine(" FillMethod: {0}", ocrZone.FillMethod)
      Console.WriteLine(" RecognitionModule: {0}", ocrZone.RecognitionModule)
      Console.WriteLine(" CharacterFilters: {0}", ocrZone.CharacterFilters)
      Console.WriteLine("----------------------------------")
   Next
End Sub
C#Copy Code
public void OcrPageExample() 
{ 
   // Unlock the support needed for LEADTOOLS Plus OCR engine 
   RasterSupport.Unlock(RasterSupportType.Document, "Replace with your own key here"); 
   RasterSupport.Unlock(RasterSupportType.OcrPlus, "Replace with your own key here"); 
   RasterSupport.Unlock(RasterSupportType.OcrPlusPdfLeadOutput, "Replace with your own key here"); 
   string tifFileName = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.tif"; 
   string pdfFileName = LeadtoolsExamples.Common.ImagesPath.Path + "Ocr1.pdf"; 
 
   // Create an instance of the engine 
   using(IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Plus, false)) 
   { 
      // Start the engine using default parameters 
      ocrEngine.Startup(null, null, null, null); 
 
      // Create an OCR document 
      using(IOcrDocument ocrDocument = ocrEngine.DocumentManager.CreateDocument()) 
      { 
         // Add this image to the document 
         IOcrPage ocrPage = ocrDocument.Pages.AddPage(tifFileName, null); 
 
         // Auto-recognize the zones in the page 
         ocrPage.AutoZone(null); 
 
         // Show its information 
         Console.WriteLine("Size: {0} by {1} pixels", ocrPage.Width, ocrPage.Height); 
         Console.WriteLine("Resolution: {0} by {1} dots/inch", ocrPage.DpiX, ocrPage.DpiX); 
         Console.WriteLine("Bits/Pixel: {0}, Bytes/Line: {1}", ocrPage.BitsPerPixel, ocrPage.BytesPerLine); 
 
         byte[] palette = ocrPage.GetPalette(); 
         int paletteEntries; 
         if(palette != null) 
            paletteEntries = palette.Length / 3; 
         else 
            paletteEntries = 0; 
 
         Console.WriteLine("Number of entries in the palette: {0}", paletteEntries); 
         Console.WriteLine("Original format of this page: {0}", ocrPage.OriginalFormat); 
         Console.WriteLine("Has this page been recognized? : {0}", ocrPage.IsRecognized); 
         ShowZonesInfo(ocrPage); 
 
         // Recognize it and save it as PDF 
         ocrPage.Recognize(null); 
         ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, null); 
      } 
 
      // Shutdown the engine 
      // Note: calling Dispose will also automatically shutdown the engine if it has been started 
      ocrEngine.Shutdown(); 
   } 
} 
 
private void ShowZonesInfo(IOcrPage ocrPage) 
{ 
   Console.WriteLine("Zones:"); 
   foreach(OcrZone ocrZone in ocrPage.Zones) 
   { 
      int index = ocrPage.Zones.IndexOf(ocrZone); 
      Console.WriteLine("Zone index: {0}", index); 
      Console.WriteLine("  Id                  {0}", ocrZone.Id); 
      Console.WriteLine("  Bounds              {0}", ocrZone.Bounds); 
      Console.WriteLine("  ZoneType            {0}", ocrZone.ZoneType); 
      Console.WriteLine("  FillMethod:         {0}", ocrZone.FillMethod); 
      Console.WriteLine("  RecognitionModule:  {0}", ocrZone.RecognitionModule); 
      Console.WriteLine("  CharacterFilters:   {0}", ocrZone.CharacterFilters); 
      Console.WriteLine("----------------------------------"); 
   } 
}

Remarks

IOcrPage defines a page currently added in the OCR engine. Each page contains the raster image used to create it (the image used when the page is loaded or added) and a group of OCR zones for the page either added manually or through auto-zoning.

You can access the pages inside the OCR document (IOcrDocument) through the IOcrDocument.Pages property. The value of this property is a IOcrPageCollection interface. This interface implements standard .NET Generic ICollection, Generic IList, and Generic IEnumerable interfaces and hence, you can use the member of these interfaces to add, remove, get, set and iterate through the different pages of the document.

You cannot create IOcrPage objects directly. Instead, add pages to the engine through the various AddPage, AddPages, InsertPage and InsertPages methods of the IOcrPageCollection interface. Once a page is added, access it by index to get the IOcrPage object associated with it.

Each page contains a collection of OCR zones. This collection can be accessed with the Zones member. This member implements the IOcrZoneCollection interface which also implements the same standard .NET collections interfaces as IOcrPageCollection. Hence you can use Zones to add, remove, get, set and iterate through the various zones in the page.

After adding a page to an OCR document and optionally manipulating the zones inside it, call the IOcrPage.Recognize or RecognizeText methods to collect the recognition data of the page. This data is stored internally in the page and can later be saved to one of the many document file formats supported by the engine such as PDF or Microsoft Word.

After a page is recognized, examine and modify the recognition data (characters and words) through the GetRecognizedCharacters and SetRecognizedCharacters methods.

Once an IOcrPage object is obtained on a page, you can do the following:

  • Get information regarding the page image, such its Width, Height, BitsPerPixel and the DPI (DpiX and DpiY) values.
  • Get a RasterImage object with the GetRasterImage method that represents the page raster image data. Manipulate this image with other parts of LEADTOOLS such as the various image processing commands or show it in the Windows Forms viewer. You can also use SetRasterImage to update the page raster image data.

Note, the LEADTOOLS Plus OCR engine does not support image sizes greater than A3 paper size (11.7 by 16.5 inches at 300 dpi). Attempting to add an image that has a size greater than A3 will result in an error. For larger documents, you must first resize the image before adding it to the LEADTOOLS Plus OCR engine. The Professional and Advantage engines do not have a restriction on the image size.

Requirements

Target Platforms: Microsoft .NET Framework 3.0, Windows XP, Windows Server 2003 family, Windows Server 2008 family

See Also

IOcrPage requires an OCR module license and unlock key. For more information, refer to: Imaging Pro/Document/Medical Features