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GetRecognizedCharacters Method
See Also  Example
Leadtools.Forms.Ocr Namespace > IOcrPage Interface : GetRecognizedCharacters Method



Gets the last recognized character data of this IOcrPage

Syntax

Visual Basic (Declaration) 
Overridable Function GetRecognizedCharacters() As IOcrPageCharacters
Visual Basic (Usage)Copy Code
Dim instance As IOcrPage
Dim value As IOcrPageCharacters
 
value = instance.GetRecognizedCharacters()
C# 
virtual IOcrPageCharacters GetRecognizedCharacters()
C++/CLI 
virtual IOcrPageCharacters^ GetRecognizedCharacters();

Return Value

An instance of IOcrPageCharacters containing the last recognized characters data of this IOcrPage.

Example

This example will get the recognized characters of a page, modify them and set them back before saving the final document.

Visual BasicCopy Code
Public Sub RecognizedCharactersExample()
   ' 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")
   ' Create an image with some text in it
   Dim image As New RasterImage(RasterMemoryFlags.Conventional, 320, 200, 24, RasterByteOrder.Bgr, RasterViewPerspective.TopLeft, Nothing, IntPtr.Zero, 0)
   Dim imageRect As New Rectangle(0, 0, image.ImageWidth, image.ImageHeight)

   Dim hdc As IntPtr = image.CreateLeadDC()
   Using g As Graphics = Graphics.FromHdc(hdc)
      g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality
      g.FillRectangle(Brushes.White, imageRect)

      Using f As New Font("Arial", 20, FontStyle.Regular)
         g.DrawString("Normal line", f, Brushes.Black, 0, 0)
      End Using

      Using f As New Font("Arial", 20, FontStyle.Bold Or FontStyle.Italic)
         g.DrawString("Bold and italic line", f, Brushes.Black, 0, 40)
      End Using

      Using f As New Font("Courier New", 20, FontStyle.Regular)
         g.DrawString("Monospaced line", f, Brushes.Black, 0, 80)
      End Using
   End Using

   RasterImage.DeleteLeadDC(hdc)

   Dim textFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "MyImageWithTest.txt"
   Dim pdfFileName As String = LeadtoolsExamples.Common.ImagesPath.Path + "MyImageWithTest.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(image, Nothing)
         image.Dispose()

         ' Recognize this page
         ocrPage.Recognize(Nothing)

         ' Dump the characters into a text file
         Using writer As StreamWriter = File.CreateText(textFileName)
            Dim ocrPageCharacters As IOcrPageCharacters = ocrPage.GetRecognizedCharacters()
            For Each ocrZoneCharacters As IOcrZoneCharacters In ocrPageCharacters
               ' Show the words found in this zone. Get the word boundaries in inches
               Dim words As ICollection(Of OcrWord) = ocrZoneCharacters.GetWords(ocrPage.DpiX, ocrPage.DpiY, LogicalUnit.Inch)
               Console.WriteLine("Words:")
               For Each word As OcrWord In words
                  Console.WriteLine("Word: {0}, at {1}, characters index from {2} to {3}", word.Value, word.Bounds, word.FirstCharacterIndex, word.LastCharacterIndex)
               Next

               Dim nextCharacterIsNewWord As Boolean = True

               For i As Integer = 0 To ocrZoneCharacters.Count - 1
                  Dim ocrCharacter As OcrCharacter = ocrZoneCharacters(i)

                  ' Capitalize the first letter if this is a new word
                  If (nextCharacterIsNewWord) Then
                     ocrCharacter.Code = Char.ToUpper(ocrCharacter.Code)
                  End If

                  writer.WriteLine("Code: {0}, Confidence: {1}, WordIsCertain: {2}, Bounds: {3}, Position: {4}, FontSize: {5}, FontStyle: {6}", _
                     ocrCharacter.Code, _
                     ocrCharacter.Confidence, _
                     ocrCharacter.WordIsCertain, _
                     ocrCharacter.Bounds, _
                     ocrCharacter.Position, _
                     ocrCharacter.FontSize, _
                     ocrCharacter.FontStyle)

                  ' If the charcater is italic, make it underline
                  If ((ocrCharacter.FontStyle And OcrCharacterFontStyle.Italic) = OcrCharacterFontStyle.Italic) Then
                     ocrCharacter.FontStyle = ocrCharacter.FontStyle And (Not OcrCharacterFontStyle.Italic)
                     ocrCharacter.FontStyle = ocrCharacter.FontStyle Or OcrCharacterFontStyle.Underline
                  End If

                  ' Check if next character is the start of a new word
                  If ((ocrCharacter.Position And OcrCharacterPosition.EndOfWord) = OcrCharacterPosition.EndOfWord OrElse _
                        (ocrCharacter.Position And OcrCharacterPosition.EndOfLine) = OcrCharacterPosition.EndOfLine) Then
                     nextCharacterIsNewWord = True
                  Else
                     nextCharacterIsNewWord = False
                  End If

                  ocrZoneCharacters(i) = ocrCharacter
               Next
            Next

            ' Replace the characters with the modified one before we save
            ocrPage.SetRecognizedCharacters(ocrPageCharacters)
         End Using

         ' Show the recognition results
         ' Set the PDF options to save as PDF/A text only
         Dim pdfOptions As PdfDocumentOptions = DirectCast(ocrEngine.DocumentWriterInstance.GetOptions(DocumentFormat.Pdf), PdfDocumentOptions)
         pdfOptions.DocumentType = PdfDocumentType.PdfA
         pdfOptions.ImageOverText = False
         ocrEngine.DocumentWriterInstance.SetOptions(DocumentFormat.Pdf, pdfOptions)

         ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, Nothing)

         ' Open and check the result file, it should contain the following text
         ' "Normal Line"
         ' "Bold And Italic Line"
         ' "Monospaced Line"
         ' With the second line bold and underlined now
      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
C#Copy Code
public void RecognizedCharactersExample() 
{ 
   // 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"); 
   // Create an image with some text in it 
   RasterImage image = new RasterImage(RasterMemoryFlags.Conventional, 640, 200, 24, RasterByteOrder.Bgr, RasterViewPerspective.TopLeft, null, IntPtr.Zero, 0); 
   Rectangle imageRect = new Rectangle(0, 0, image.ImageWidth, image.ImageHeight); 
 
   IntPtr hdc = image.CreateLeadDC(); 
   using(Graphics g = Graphics.FromHdc(hdc)) 
   { 
      g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality; 
      g.FillRectangle(Brushes.White, imageRect); 
 
      using(Font f = new Font("Arial", 20, FontStyle.Regular)) 
         g.DrawString("Normal line", f, Brushes.Black, 0, 0); 
 
      using(Font f = new Font("Arial", 20, FontStyle.Bold)) 
         g.DrawString("Bold, italic and underline", f, Brushes.Black, 0, 40); 
 
      using(Font f = new Font("Courier New", 20, FontStyle.Regular)) 
         g.DrawString("Monospaced line", f, Brushes.Black, 0, 80); 
   } 
 
   RasterImage.DeleteLeadDC(hdc); 
 
   string textFileName = LeadtoolsExamples.Common.ImagesPath.Path + "MyImageWithTest.txt"; 
   string pdfFileName = LeadtoolsExamples.Common.ImagesPath.Path + "MyImageWithTest.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(image, null); 
         image.Dispose(); 
 
         // Recognize this page 
         ocrPage.Recognize(null); 
 
         // Dump the characters into a text file 
         using(StreamWriter writer = File.CreateText(textFileName)) 
         { 
            IOcrPageCharacters ocrPageCharacters = ocrPage.GetRecognizedCharacters(); 
            foreach(IOcrZoneCharacters ocrZoneCharacters in ocrPageCharacters) 
            { 
               // Show the words found in this zone. Get the word boundaries in inches 
               ICollection<OcrWord> words = ocrZoneCharacters.GetWords(ocrPage.DpiX, ocrPage.DpiY, LogicalUnit.Inch); 
               Console.WriteLine("Words:"); 
               foreach(OcrWord word in words) 
                  Console.WriteLine("Word: {0}, at {1}, characters index from {2} to {3}", word.Value, word.Bounds, word.FirstCharacterIndex, word.LastCharacterIndex); 
 
               bool nextCharacterIsNewWord = true; 
 
               for(int i = 0; i < ocrZoneCharacters.Count; i++) 
               { 
                  OcrCharacter ocrCharacter  = ocrZoneCharacters[i]; 
 
                  // Capitalize the first letter if this is a new word 
                  if(nextCharacterIsNewWord) 
                     ocrCharacter.Code = Char.ToUpper(ocrCharacter.Code); 
 
                  writer.WriteLine("Code: {0}, Confidence: {1}, WordIsCertain: {2}, Bounds: {3}, Position: {4}, FontSize: {5}, FontStyle: {6}", 
                     ocrCharacter.Code, 
                     ocrCharacter.Confidence, 
                     ocrCharacter.WordIsCertain, 
                     ocrCharacter.Bounds, 
                     ocrCharacter.Position, 
                     ocrCharacter.FontSize, 
                     ocrCharacter.FontStyle); 
 
                  // If the charcater is bold, make it underline 
                  if((ocrCharacter.FontStyle & OcrCharacterFontStyle.Bold) == OcrCharacterFontStyle.Bold) 
                  { 
                     ocrCharacter.FontStyle |= OcrCharacterFontStyle.Italic; 
                     ocrCharacter.FontStyle |= OcrCharacterFontStyle.Underline; 
                  } 
 
                  // Check if next character is the start of a new word 
                  if((ocrCharacter.Position & OcrCharacterPosition.EndOfWord) == OcrCharacterPosition.EndOfWord || 
                     (ocrCharacter.Position & OcrCharacterPosition.EndOfLine) == OcrCharacterPosition.EndOfLine) 
                     nextCharacterIsNewWord = true; 
                  else 
                     nextCharacterIsNewWord = false; 
 
                  ocrZoneCharacters[i] = ocrCharacter; 
               } 
            } 
 
            // Replace the characters with the modified one before we save 
            ocrPage.SetRecognizedCharacters(ocrPageCharacters); 
         } 
 
         // Show the recognition results 
         // Set the PDF options to save as PDF/A text only 
         PdfDocumentOptions pdfOptions = ocrEngine.DocumentWriterInstance.GetOptions(DocumentFormat.Pdf) as PdfDocumentOptions; 
         pdfOptions.DocumentType = PdfDocumentType.PdfA; 
         pdfOptions.ImageOverText = false; 
         ocrEngine.DocumentWriterInstance.SetOptions(DocumentFormat.Pdf, pdfOptions); 
 
         ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, null); 
 
         // Open and check the result file, it should contain the following text 
         // "Normal Line" 
         // "Bold And Italic Line" 
         // "Monospaced Line" 
         // With the second line bold and underlined now 
      } 
 
      // Shutdown the engine 
      // Note: calling Dispose will also automatically shutdown the engine if it has been started 
      ocrEngine.Shutdown(); 
   } 
}

Remarks

You must call this method after the IOcrPage has been recognized with the IOcrPage.Recognize or RecognizeText method. i.e., if the value of the IsRecognized property of this page is false, then calling this method will throw an exception.

You can use the GetRecognizedCharacters to examine the recognized character data. This data contain information about the character codes, their confidence, guess codes, location and position in the page as well as font information. For more information, refer to OcrCharacter.

The GetRecognizedCharacters method returns an instance of IOcrPageCharacters, this instance is a collection of IOcrZoneCharacters. The IOcrZoneCharacters.ZoneIndex property contains the zero-based index of the zone. You can get the zone information by using the same index as the Zones property of this IOcrPage.

If you wish to modify and the apply recognition data back to the page, Use SetRecognizedCharacters.

Use IOcrZoneCharacters.GetWords to get the recognized words of a zone.

Notes on spaces: The LEADTOOLS Plus and Advantage OCR engines will not return any space characters when using the GetRecognizedCharacters method.

The LEADTOOLS Professional OCR engine will not return space characters if the value of the boolean Recognition.SpaceIsValidCharacter setting value is false (the default). If you absolutely require space characters in the recognition results when using the LEADTOOLS Professional Engine, then set the value of the boolean Recognition.SpaceIsValidCharacter setting to true ( ocrEngineInstance.SettingManager.SetBooleanValue("Recognition.SpaceIsValidCharacter", true)). For more information on OCR settings, refer to IOcrSettingManager and LEADTOOLS OCR Professional Engine Settings.

The SetRecognizedCharacters method will accept space characters in the LEADTOOLS Plus and Advantage engines. However, these space characters will be used when generating the final document (PDF) and might affect the final output. Therefore, it is not recommended that you insert space characters when using the LEADTOOLS Plus and Advantage engines.

The LEADTOOLS Professional OCR engine will strip any space characters from the results passed to SetRecognizedCharacters if the value of the boolean Recognition.SpaceIsValidCharacter setting value is false (the default). If you absolutely require space characters in the recognition results when using the LEADTOOLS Professional Engine, then set the value of the boolean Recognition.SpaceIsValidCharacter setting to true before calling SetRecognizedCharacters.

If you use the GetRecognizedCharacters and SetRecognizedCharacters methods to modify the recognition result prior to saving to an output file, and you are planning on using the engine native save capability (through setting the IOcrDocumentManager.EngineFormat property and using DocumentFormat.User in the IOcrDocument.Save method), then you must change the boolean Recognition.SpaceIsValidCharacter setting to true.

Requirements

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

See Also

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