RecognizeText Method

Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.Forms.Ocr
Imports Leadtools.Forms
Imports Leadtools.WinForms
Imports Leadtools.Drawing

Public Sub RecognizeTextExample()
   ' Get the form file name
   Console.WriteLine("Setting up the form...")
   Dim formFileName As String = GetMyForm()
   ' Assume we get the field informations from an external source such as a database or an XML file
   Dim fieldNames() As String = _
   { _
      "Name", _
      "Address", _
      "SSN" _
   }

   Dim fieldBounds() As LogicalRectangle = _
   { _
      New LogicalRectangle(800, 160, 1500, 220, LogicalUnit.Pixel), _
      New LogicalRectangle(800, 560, 1500, 220, LogicalUnit.Pixel), _
      New LogicalRectangle(800, 960, 1500, 220, LogicalUnit.Pixel) _
   }

   Dim fieldCount As Integer = fieldNames.Length
   Dim fieldValues(fieldCount - 1) As String

   ' Create an instance of the engine
   Using ocrEngine As IOcrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Advantage, False)
      ' Start the engine using default parameters
      Console.WriteLine("Starting up the engine...")
      ocrEngine.Startup(Nothing, Nothing, Nothing, LEAD_VARS.OcrAdvantageRuntimeDir)

      ' Create an OCR document
      Dim ocrDocumentManager As IOcrDocumentManager = ocrEngine.DocumentManager
      Using ocrDocument As IOcrDocument = ocrDocumentManager.CreateDocument()

         ' Add the form to the document
         Console.WriteLine("Adding the form to the document...")
         Dim ocrPage As IOcrPage = ocrDocument.Pages.AddPage(formFileName, Nothing)

         ' Get our fields
         For i As Integer = 0 To fieldCount - 1
            ' Clear all the zones in the page
            ocrPage.Zones.Clear()

            ' Add our field zone
            Dim ocrZone As New OcrZone()
            ocrZone.ZoneType = OcrZoneType.Text
            ocrZone.Bounds = fieldBounds(i)
            ocrZone.Name = fieldNames(i) ' Optional

            Console.WriteLine("Adding the zone for field {0} to the page...", ocrZone.Name)
            ocrPage.Zones.Add(ocrZone)

            ' Recognize the page. This will only recognize the zone we added
            Console.WriteLine("Recognizing the page...")
            fieldValues(i) = ocrPage.RecognizeText(Nothing)
         Next

      End Using

      ' Shutdown the engine
      ' Note: calling Dispose will also automatically shutdown the engine if it has been started
      Console.WriteLine("Shutting down...")
      ocrEngine.Shutdown()
   End Using

   ' We are done, show the fields
   Console.WriteLine("-------------------------------------")
   Console.WriteLine("Done, values extracted from the form:")
   Console.WriteLine("-------------------------------------")
   For i As Integer = 0 To fieldCount - 1
      Console.WriteLine("{0} : {1}", fieldNames(i), fieldValues(i))
   Next
End Sub

Private Function GetMyForm() As String
   Dim formFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "MyForm.tif")

   ' In this example we will create the form every time
   ' This will be a TIF file 11 by 8.5 inches in size containing a name, address and social security fields
   Using image As RasterImage = New RasterImage( _
         RasterMemoryFlags.Conventional, _
         2544, _
         3294, _
         24, _
         RasterByteOrder.Bgr, _
         RasterViewPerspective.BottomLeft, _
         Nothing, _
         IntPtr.Zero, _
         0)
      image.XResolution = 300
      image.YResolution = 300

      ' Draw our fields into this image
      Dim hdc As IntPtr = RasterImagePainter.CreateLeadDC(image)

      Try
         Using g As Graphics = Graphics.FromHdc(hdc)
            g.FillRectangle(Brushes.White, 0, 0, image.ImageWidth - 1, image.ImageHeight - 1)

            Using f As New Font("Times New Roman", 80, FontStyle.Regular)
               Using p As New Pen(Color.Black, 4)
                  Using sf As New StringFormat()
                     sf.LineAlignment = StringAlignment.Center
                     ' Draw the fields

                     ' Name
                     g.DrawString("Name:", f, Brushes.Black, 200, 200)
                     Dim rc As New Rectangle(800, 160, 1500, 220)
                     g.DrawRectangle(p, rc)
                     Dim value As String = "John Doe"
                     g.DrawString(value, f, Brushes.Black, rc, sf)

                     ' Address
                     g.DrawString("Address:", f, Brushes.Black, 200, 600)
                     rc = New Rectangle(800, 560, 1500, 220)
                     g.DrawRectangle(p, rc)
                     value = "1234 Main Street, USA"
                     g.DrawString(value, f, Brushes.Black, rc, sf)

                     ' Social security number
                     g.DrawString("SSN:", f, Brushes.Black, 200, 1000)
                     rc = New Rectangle(800, 960, 1500, 220)
                     g.DrawRectangle(p, rc)
                     value = "123-45-6789"
                     g.DrawString(value, f, Brushes.Black, rc, sf)
                  End Using
               End Using
            End Using
         End Using
      Finally
         RasterImagePainter.DeleteLeadDC(hdc)
      End Try

      ' Save this image to disk
      Using codecs As New RasterCodecs()
         codecs.Save(image, formFileName, RasterImageFormat.CcittGroup4, 1)
      End Using
   End Using

   Return formFileName
End Function

Public NotInheritable Class LEAD_VARS
Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
Public Const OcrAdvantageRuntimeDir As String = "C:\LEADTOOLS 18\Bin\Common\OcrAdvantageRuntime"
End Class