RecognizeText Method

'Declaration
 
Function RecognizeText( _
   ByVal callback As OcrProgressCallback _
) As String

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.Plus, False)
         ' Start the engine using default parameters
         Console.WriteLine("Starting up the engine...")
         ocrEngine.Startup(Nothing, Nothing, Nothing, Nothing)

         ' 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"
End Class