OCR Tutorial - Working with Pages

Take the following steps to create and run a program that shows how to work with pages in an OCR document. Remember, the purpose of the tutorials is to provide you with a quick and easy way to generate an OCR program.

Start Visual Studio
Choose File->New->Project from the menu.
In the New Project dialog box, choose either "Visual C# Projects" or "Visual Basic Projects" in the Projects Type List, and choose "Windows Application" or "Windows Forms Application" depending on your Visual Studio Version from the Templates List.
Type the project name as "OcrTutorial" 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.
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 "<LEADTOOLS_INSTALLDIR>\Bin\DotNet4\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.Advantage.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 formats. Add any additional file format codec DLL if required in your application.

Drag and drop five 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	Startup
button2	Add Page
button3	Remove Pages
button4	Flip Page
button5	Shutdown

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 using or Imports section if there are any:

[C#]


             using Leadtools;
             using Leadtools.Codecs;
             using Leadtools.Forms;
             using Leadtools.Forms.DocumentWriters;
             using Leadtools.Forms.Ocr;
             using Leadtools.ImageProcessing;

[Visual Basic]


             Imports Leadtools
             Imports Leadtools.Codecs
             Imports Leadtools.Forms
             Imports Leadtools.Forms.DocumentWriters
             Imports Leadtools.Forms.Ocr
             Imports Leadtools.ImageProcessing

Add the following private variables to the Form1 class:

[C#]


             private IOcrEngine _ocrEngine;
             private IOcrDocument _ocrDocument;

[Visual Basic]


             Private _ocrEngine As IOcrEngine
             Private _ocrDocument As IOcrDocument

Add the following code for the button1 (Startup) Click handler:

[C#]


             private void button1_Click(object sender, EventArgs e)
             {
                // Initialize the OCR engine
                _ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Advantage, false);
                // Start it up
                _ocrEngine.Startup(null, null, null, @"C:\LEADTOOLS 19\Bin\Common\OcrAdvantageRuntime");
                // Create the document
                 _ocrDocument = _ocrEngine.DocumentManager.CreateDocument();
                MessageBox.Show("OCR engine has been started successfully and document created");
             }

[Visual Basic]


             Private Sub button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button1.Click
                ' Initialize the OCR engine
                _ocrEngine = OcrEngineManager.CreateEngine(OcrEngineType.Advantage, False)
                ' Start it up
                _ocrEngine.Startup(Nothing, Nothing, Nothing, "C:\LEADTOOLS 19\Bin\Common\OcrAdvantageRuntime")
                ' Create the document
                 _ocrDocument = _ocrEngine.DocumentManager.CreateDocument()
                MessageBox.Show("OCR engine has been started successfully and document created")
             End Sub

Add the following code for the button2 (Add Page) Click handler:

[C#]


             private void button2_Click(object sender, EventArgs e)
             {
                // Browse to an existing document file on disk, for example @"C:\Users\Public\Documents\LEADTOOLS Images\Ocr1.tif";
                string fileName = null;
                using (OpenFileDialog dlg = new OpenFileDialog())
                {
                   if (dlg.ShowDialog(this) == DialogResult.OK)
                      fileName = dlg.FileName;
                }
            
                if (fileName == null)
                   return;
            
                // Add the first page from the file to the OCR document
                IOcrPage page = _ocrDocument.Pages.AddPage(fileName, null);
                int pageCount = _ocrDocument.Pages.Count;
                // Show some information about this page
                string message = string.Format(
                   "Total pages is {0}\nLast page added size = {1} by {2}\nResolution = {3} by {4}\nBits per pixel = {5}",
                   pageCount,
                   page.Width, page.Height,
                   page.DpiX, page.DpiY,
                   page.BitsPerPixel);
                MessageBox.Show(message);
             }

[Visual Basic]


             Private Sub button2_Click(sender As Object, e As EventArgs)
                ' Browse to an existing document file on disk, for example @"C:\Users\Public\Documents\LEADTOOLS Images\Ocr1.tif";
                Dim fileName As String = Nothing
                Using dlg As New OpenFileDialog()
                   If dlg.ShowDialog(Me) = DialogResult.OK Then
                      fileName = dlg.FileName
                   End If
                End Using
            
                If IsNothing(fileName) Then Return
            
                ' Add the first page from the file to the OCR document
                Dim page As IOcrPage = _ocrDocument.Pages.AddPage(fileName, Nothing)
                Dim pageCount As Integer = _ocrDocument.Pages.Count
                ' Show some information about this page
                Dim message As String = String.Format( _
                   "Total pages is {0}\nLast page added size = {1} by {2}\nResolution = {3} by {4}\nBits per pixel = {5}", _
                   pageCount, _
                   page.Width, page.Height, _
                   page.DpiX, page.DpiY, _
                   page.BitsPerPixel)
                MessageBox.Show(message)
             End Sub

Add the following code for the button3 (Remove Pages) Click handler:

[C#]


             private void button3_Click(object sender, EventArgs e)
             {
                // Remove all added pages from the OCR document
                _ocrDocument.Pages.Clear();
                MessageBox.Show("All the pages has been removed");
             }

[Visual Basic]


             Private Sub button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button3.Click
                ' Remove all added pages from the OCR document
                _ocrDocument.Pages.Clear()
                MessageBox.Show("All the pages has been removed")
             End Sub

Add the following code for the button4 (Flip Page) Click handler:

[C#]


             private void button4_Click(object sender, EventArgs e)
             {
                // Get the last page added to the OCR document
                if (_ocrDocument.Pages.Count < 1)
                   return;
            
                IOcrPage page = _ocrDocument.Pages[_ocrDocument.Pages.Count - 1];
                // Get a RasterImage that represents this page
                using (RasterImage image = page.GetRasterImage())
                {
                   // Flip this image vertically
                   FlipCommand cmd = new FlipCommand(false);
                   cmd.Run(image);
                   // The RasterImage is a copy of the page, so update it
                   page.SetRasterImage(image);
                   MessageBox.Show("Last page has been flipped");
                }
             }

[Visual Basic]


             Private Sub button4_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button4.Click
                ' Get the last page added to the OCR document
                If (_ocrDocument.Pages.Count < 1) Then
                   Return
                End If
                Dim page As IOcrPage = _ocrDocument.Pages(_ocrDocument.Pages.Count - 1)
                ' Get a RasterImage that represents this page
                Using image As RasterImage = page.GetRasterImage()
                   ' Flip this image vertically
                   Dim cmd As New FlipCommand(False)
                   cmd.Run(image)
                   ' The RasterImage is a copy of the page, so update it
                   page.SetRasterImage(image)
                   MessageBox.Show("Last page has been flipped")
                End Using
             End Sub

Add the following code for the button5 (Shutdown) Click handler:

[C#]


             private void button5_Click(object sender, EventArgs e)
             {
                // Destroy the document
                _ocrDocument.Dispose();
                // Destroy the engine (will also shut it down)
                _ocrEngine.Dispose();
                MessageBox.Show("OCR engine and document has been destroyed")
             }

[Visual Basic]


             Private Sub button5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles button5.Click
                ' Destroy the document
                _ocrDocument.Dispose()
                ' Destroy the engine (will also shut it down)
                _ocrEngine.Dispose()
                MessageBox.Show("OCR engine and document has been destroyed")
             End Sub

Build, and Run the program to test it.
Save this project to use for testing other code samples.

Reference

OCR Tutorial - Recognizing Pages
OCR Tutorial - Adding and Painting Zones
OCR Tutorial - Working with Recognition Results
OCR Tutorial - Scanning to Searchable PDF
Introduction
Getting Started (Guide to Example Programs)
LEADTOOLS OCR .NET Assemblies
Programming with LEADTOOLS .NET OCR
An Overview of OCR Recognition Modules
Creating an OCR Engine Instance
Starting and Shutting Down the OCR Engine
Multi-Threading with LEADTOOLS OCR
OCR Spell Language Dictionaries
Working with OCR Languages
Working with OCR Pages
Working with OCR Zones
Recognizing OCR Pages
OCR Confidence Reporting
Using OMR in LEADTOOLS .NET OCR
OCR Languages and Spell Checking
OCR Engine-Specific Settings