Take the following steps to create and run a program that shows how scan a document and convert it to a searchable PDF file.

1. Start Visual Studio 2005 or 2008

2. Choose File->New->Project from the menu

3. In the New Project dialog box, choose either "Visual C# Projects" or "Visual Basic Projects" in the Projects Type List, and choose "Windows Application" in Visual Studio 2005 or "Windows Forms Application" in Visual Studio 2008 from the Templates List

4. Type the project name as "OcrTutorial3" in the Project Name field, and then choose OK. If desired, type a new location for your project or select a directory using the Browse button, and then choose OK.

5. In the "Solution Explorer" window, right-click on the "References" folder, and select "Add Reference..." from the context menu. In the "Add Reference" dialog box, select the ".NET" tab and browse to LEADTOOLS For .NET "\LEAD Technologies\LEADTOOLS 16.5\Bin\DotNet\Win32" folder and select the following DLLs:

   • Leadtools.dll
   • Leadtools.Codecs.dll
   • Leadtools.Forms.dll
   • Leadtools.Forms.DocumentWriters.dll
   • Leadtools.Forms.Ocr.dll
   • Leadtools.Forms.Ocr.Plus.dll
   • Leadtools.Twain.dll
   • Leadtools.ImageProcessing.Core.dll
   • Leadtools.Codecs.Bmp.dll
   • Leadtools.Codecs.Cmp.dll
   • Leadtools.Codecs.Tif.dll
   • Leadtools.Codecs.Fax.dll

   Note: The Leadtools.Codecs.*.dll references added are for the BMP, JPG, CMP, TIF and FAX image file formats. Add any additional file format codec DLL if required in your application.

6. Drag and drop three buttons in Form1. Leave all the buttons names as the default "button1, button2 ...", then change the Text property of each button to the following:

   Button	Text
   button1	Change output directory
   button2	Select the Scanner
   button3	Scan and OCR

7. Switch to Form1 code view (Right-click Form1 in the solution explorer then select View Code) and add the following lines at the beginning of the file after any Imports or using section if there are any:

   [Visual Basic]

   
   Imports Leadtools
   Imports Leadtools.Twain
   Imports Leadtools.Forms
   Imports Leadtools.Forms.DocumentWriters
   Imports Leadtools.Forms.Ocr
   Imports Leadtools.ImageProcessing.Core
        

   [C#]

   
   using Leadtools;
   using Leadtools.Twain;
   using Leadtools.Forms;
   using Leadtools.Forms.DocumentWriters;
   using Leadtools.Forms.Ocr;
   using Leadtools.ImageProcessing.Core;
        

8. Add the following private variable to the Form1 class:

   [Visual Basic]

   
   ' The OCR engine instance
   Private _ocrEngine As IOcrEngine
   ' The OCR document
   Private _ocrDocument As IOcrDocument
   ' The Twain session
   Private _twainSession As TwainSession
   ' The output directory for saving PDF files
   Private _outputDirectory As String = "C:\MyImages"
   ' The image processing commands we are going to use to clean the scanned image
   Private deskewCmd As DeskewCommand
   Private despeckleCmd As DespeckleCommand
   Private dotRemoveCmd As DotRemoveCommand
   Private holePunchRemoveCmd As HolePunchRemoveCommand
   Private lineRemoveCmd As LineRemoveCommand
        

   [C#]

   
   // The OCR engine instance
   private IOcrEngine _ocrEngine;
   // The OCR document
   private IOcrDocument _ocrDocument;
   // The Twain session
   private TwainSession _twainSession;
   // The output directory for saving PDF files
   private string _outputDirectory = @"C:\MyImages";
   // The image processing commands we are going to use to clean the scanned image
   private DeskewCommand deskewCmd;
   private DespeckleCommand despeckleCmd;
   private DotRemoveCommand dotRemoveCmd;
   private HolePunchRemoveCommand holePunchRemoveCmd;
   private LineRemoveCommand lineRemoveCmd;
        

9. Add the following code to the Form1 constructor (in Visual Basic, you can copy/paste the whole Sub New code from here):

   [Visual Basic]

   
   Sub New()
      ' This call is required by the Windows Form Designer.
      InitializeComponent()
   
      ' Add any initialization after the InitializeComponent() call.
   
      ' Unlock the OCR support
      RasterSupport.Unlock(RasterSupportType.OcrPlus, "testkey")
      ' Unlock the PDF save support
      RasterSupport.Unlock(RasterSupportType.OcrPlusPdfLeadOutput, "testkey")
      ' Unlock Document support
      RasterSupport.Unlock(RasterSupportType.Document, "testkey")
   
      ' Initialize the OCR engine
      _ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Plus, False)
   
      ' Startup the engine
      _ocrEngine.Startup(Nothing, Nothing, Nothing, Nothing)
   
      ' Create the OCR document
      _ocrDocument = _ocrEngine.DocumentManager.CreateDocument()
   
      ' Initalize Twain scanning session
      _twainSession = New TwainSession()
      _twainSession.Startup(Me, "My Company", "My Product", "My Version", "My Application", TwainStartupFlags.None)
   
      ' Subscribe to the TwainSession.Acquire event to get the image
      AddHandler _twainSession.AcquirePage, AddressOf _twainSession_AcquirePage
   
      ' Initialize the image processing commands we are going to use
   
      ' Initialize Deskew
      deskewCmd = New DeskewCommand()
   
      ' Initialize Despeckle
      despeckleCmd = New DespeckleCommand()
   
      ' Initialize DotRemove
      dotRemoveCmd = New DotRemoveCommand()
      dotRemoveCmd.Flags = _
         DotRemoveCommandFlags.UseDiagonals Or _
         DotRemoveCommandFlags.UseSize
      dotRemoveCmd.MaximumDotHeight = 8
      dotRemoveCmd.MaximumDotWidth = 8
      dotRemoveCmd.MinimumDotHeight = 2
      dotRemoveCmd.MinimumDotWidth = 2
   
      ' Initialize HolePunchRemove
      holePunchRemoveCmd = New HolePunchRemoveCommand()
      holePunchRemoveCmd.Flags = _
         HolePunchRemoveCommandFlags.UseDpi Or _
         HolePunchRemoveCommandFlags.UseCount Or _
         HolePunchRemoveCommandFlags.UseLocation
      holePunchRemoveCmd.Location = HolePunchRemoveCommandLocation.Left
   
      ' Initialize LineRemove
      lineRemoveCmd = New LineRemoveCommand()
      lineRemoveCmd.MaximumLineWidth = 9
      lineRemoveCmd.MinimumLineLength = 400
      lineRemoveCmd.Wall = 15
      lineRemoveCmd.MaximumWallPercent = 10
      lineRemoveCmd.Variance = 3
      lineRemoveCmd.GapLength = 3
   End Sub
        

   [C#]

   
   public Form1()
   {
      InitializeComponent();
   
      // Unlock the OCR support
      RasterSupport.Unlock(RasterSupportType.OcrPlus, "Replace with your own key here");
      // Unlock the PDF save support
      RasterSupport.Unlock(RasterSupportType.OcrPlusPdfLeadOutput, "Replace with your own key here");
      // Unlock Document support
      RasterSupport.Unlock(RasterSupportType.Document, "Replace with your own key here");
   
      // Initialize the OCR engine
      _ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Plus, false);
   
      // Startup the engine
      _ocrEngine.Startup(null, null, null, null);
   
      // Create the OCR document
      _ocrDocument = _ocrEngine.DocumentManager.CreateDocument();
   
      // Initalize Twain scanning session
      _twainSession = new TwainSession();
      _twainSession.Startup(this, "My Company", "My Product", "My Version", "My Application", TwainStartupFlags.None);
   
      // Subscribe to the TwainSession.Acquire event to get the image
      _twainSession.AcquirePage += new EventHandler<TwainAcquirePageEventArgs>(_twainSession_AcquirePage);
   
      // Initialize the image processing commands we are going to use
   
      // Initialize Deskew
      deskewCmd = new DeskewCommand();
   
      // Initialize Despeckle
      despeckleCmd = new DespeckleCommand();
   
      // Initialize DotRemove
      dotRemoveCmd = new DotRemoveCommand();
      dotRemoveCmd.Flags =
         DotRemoveCommandFlags.UseDiagonals |
         DotRemoveCommandFlags.UseSize;
      dotRemoveCmd.MaximumDotHeight = 8;
      dotRemoveCmd.MaximumDotWidth = 8;
      dotRemoveCmd.MinimumDotHeight = 2;
      dotRemoveCmd.MinimumDotWidth = 2;
   
       // Initialize HolePunchRemove
      holePunchRemoveCmd = new HolePunchRemoveCommand();
      holePunchRemoveCmd.Flags =
         HolePunchRemoveCommandFlags.UseDpi |
         HolePunchRemoveCommandFlags.UseCount |
         HolePunchRemoveCommandFlags.UseLocation;
      holePunchRemoveCmd.Location = HolePunchRemoveCommandLocation.Left;
   
      // Initialize LineRemove
      lineRemoveCmd = new LineRemoveCommand();
      lineRemoveCmd.MaximumLineWidth = 9;
      lineRemoveCmd.MinimumLineLength = 400;
      lineRemoveCmd.Wall = 15;
      lineRemoveCmd.MaximumWallPercent = 10;
      lineRemoveCmd.Variance = 3;
      lineRemoveCmd.GapLength = 3;
   }
        

10. Override the Form1 closed event to add the code necessary to shutdown the OCR engine when the application terminates:

    [Visual Basic]

    
    Protected Overrides Sub OnFormClosed(ByVal e As FormClosedEventArgs)
       ' Destroy the OCR document
       _ocrDocument.Dispose()
    
       ' Shutdown and dispose the OCR engine
       _ocrEngine.Dispose()
    
       ' Close the Twain session
       _twainSession.Shutdown()
    
       MyBase.OnFormClosed(e)
    End Sub
         

    [C#]

    
    protected override void OnFormClosed(FormClosedEventArgs e)
    {
       // Destroy the OCR document
       _ocrDocument.Dispose();
    
       // Shutdown and dispose the OCR engine
       _ocrEngine.Dispose();
    
       // Close the Twain session
       _twainSession.Shutdown();
    
       base.OnFormClosed(e);
    }
         

11. Add the following code for the button1 (Change output directory) control’s Click handler:

    [Visual Basic]

    
    Private Sub button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button1.Click
       ' Change the output directory
       Dim dlg As New FolderBrowserDialog()
       dlg.SelectedPath = _outputDirectory
       dlg.ShowNewFolderButton = True
       If (dlg.ShowDialog(Me) = DialogResult.OK) Then
          _outputDirectory = System.IO.Path.GetFullPath(dlg.SelectedPath)
       End If
    End Sub
         

    [C#]

    
    private void button1_Click(object sender, EventArgs e)
    {
       // Change the output directory
       FolderBrowserDialog dlg = new FolderBrowserDialog();
       dlg.SelectedPath = _outputDirectory;
       dlg.ShowNewFolderButton = true;
       if(dlg.ShowDialog(this) == DialogResult.OK)
          _outputDirectory = System.IO.Path.GetFullPath(dlg.SelectedPath);
    }
         

12. Add the following code for the button2 (Select the Scanner) control’s Click handler:

    [Visual Basic]

    
    Private Sub button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button2.Click
       ' Select the scanner to use
       _twainSession.SelectSource(Nothing)
    End Sub
         

    [C#]

    
    private void button2_Click(object sender, EventArgs e)
    {
       // Select the scanner to use
       _twainSession.SelectSource(null);
    }
         

13. Add the following code for the button3 (Scan and OCR) control’s Click handler:

    [Visual Basic]

    
    Private Sub button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button3.Click
       ' Create the output directory if it does not exist
       If (Not System.IO.Directory.Exists(_outputDirectory)) Then
          System.IO.Directory.CreateDirectory(_outputDirectory)
       End If
    
       ' Build the output PDF file name
       Dim pdfFileName As String = System.IO.Path.Combine(_outputDirectory, "Scanned.pdf")
    
       ' First remove all the pages added to the OCR document
       _ocrDocument.Pages.Clear()
    
       ' Scan the new page(s)
       _twainSession.Acquire(TwainUserInterfaceFlags.Show)
    
       ' The pages should be added to the OCR document now.
       ' Recognize and save as PDF
       _ocrDocument.Pages.Recognize(Nothing)
       _ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, Nothing)
    
       ' Show the result PDF file
       System.Diagnostics.Process.Start(pdfFileName)
    End Sub
         

    [C#]

    
    private void button3_Click(object sender, EventArgs e)
    {
       // Create the output directory if it does not exist
       if(!System.IO.Directory.Exists(_outputDirectory))
          System.IO.Directory.CreateDirectory(_outputDirectory);
    
       // Build the output PDF file name
       string pdfFileName = System.IO.Path.Combine(_outputDirectory, "Scanned.pdf");
    
       // First remove all the pages added to the OCR document
       _ocrDocument.Pages.Clear();
    
       // Scan the new page(s)
       _twainSession.Acquire(TwainUserInterfaceFlags.Show);
    
       // The pages should be added to the OCR document now.
       // Recognize and save as PDF
       _ocrDocument.Pages.Recognize(null);
       _ocrDocument.Save(pdfFileName, DocumentFormat.Pdf, null);
    
       // Show the result PDF file
       System.Diagnostics.Process.Start(pdfFileName);
    }
         

14. Add the private method to handle the AcquirePage event of the TwainSession object:

    [Visual Basic]

    
    Private Sub _twainSession_AcquirePage(ByVal sender As Object, ByVal e As TwainAcquirePageEventArgs)
       ' We have a page
       Dim image As RasterImage = e.Image
    
       ' First, run the image processing commands on it
       ' Deskew
       deskewCmd.Run(image)
    
       ' Despeckle
       despeckleCmd.Run(image)
    
       ' The rest of the commands only work on 1 BPP image
       If (image.BitsPerPixel = 1) Then
          ' Dot Remove
          dotRemoveCmd.Run(image)
    
          ' Hole Punch Remove
          holePunchRemoveCmd.Run(image)
    
          ' Vertical Line Remove
          lineRemoveCmd.Type = LineRemoveCommandType.Vertical
          lineRemoveCmd.Run(image)
    
          ' Horizontal Line Remove
          lineRemoveCmd.Type = LineRemoveCommandType.Horizontal
          lineRemoveCmd.Run(image)
       End If
    
       ' Add the image as a new page to the OCR document
       _ocrDocument.Pages.AddPage(image, Nothing)
    End Sub
         

    [C#]

    
    private void _twainSession_AcquirePage(object sender, TwainAcquirePageEventArgs e)
    {
       // We have a page
       RasterImage image = e.Image;
    
       // First, run the image processing commands on it
       // Deskew
       deskewCmd.Run(image);
    
       // Despeckle
       despeckleCmd.Run(image);
    
       // The rest of the commands only work on 1 BPP image
       if(image.BitsPerPixel == 1)
       {
          // Dot Remove
          dotRemoveCmd.Run(image);
    
          // Hole Punch Remove
          holePunchRemoveCmd.Run(image);
    
          // Vertical Line Remove
          lineRemoveCmd.Type = LineRemoveCommandType.Vertical;
          lineRemoveCmd.Run(image);
    
          // Horizontal Line Remove
          lineRemoveCmd.Type = LineRemoveCommandType.Horizontal;
          lineRemoveCmd.Run(image);
       }
    
       // Add the image as a new page to the OCR document
       _ocrDocument.Pages.AddPage(image, null);
    }
         

Reference