LoadZones(String) Method

Load zones from a multi-page zones disk file.

Syntax

Visual Basic
C#
WinRT C#
WinRT JavaScript
C++

void LoadZones( 
   string fileName
)

'Declaration
 
Overloads Sub LoadZones( _
   ByVal fileName As String _
)

'Usage
 
Dim instance As IOcrDocument
Dim fileName As String
 
instance.LoadZones(fileName)

void LoadZones( 
   string fileName
)

function Leadtools.Forms.Ocr.IOcrDocument.LoadZones(String)( 
   fileName 
)

void LoadZones( 
   String^ fileName
)

Parameters

fileName: The name of the file containing the zones to load.

Remarks

To save and load the zones of OCR pages, you can use one of these methods:

IOcrPage.SaveZones(fileName) or IOcrPage.SaveZones(stream): These methods save the zones of a particular OCR page to a single-page disk file or stream. These methods will not use the page number, and hence, the file or stream will contain zones that are not tied to any particular page and can be loaded back into any OCR page regardless of its number. To load these zones back into any OCR page, use IOcrPage.LoadZones(fileName) or IOcrPage.LoadZones(stream).
IOcrPage.SaveZones(fileName, pageNumber) or IOcrPage.SaveZones(stream, pageNumber): These methods save the zones of a particular OCR page to a multi-page disk file or stream. If the file or stream exist previously, these methods will replace the zones specified in 'pageNumber' with the zones of the IOcrPage. If the file or stream does not contain zones for the specified page number, the zones will be appended to the file or stream at the end and can be loaded later using IOcrPage.LoadZones(fileName, pageNumber) or IOcrPage.LoadZones(stream, pageNumber).
IOcrDocument.SaveZones(fileName) or IOcrDocument.SaveZones(stream): These methods save the zones of all the OCR pages in a document to a multi-page disk file or stream. The saved data will contain the page number of the zones. To load these zones, you can either use IOcrDocument.LoadZones(fileName) or IOcrDocument.LoadZones(stream) to load the zones from a multi-page file or stream back into a multi-page OCR document. Or IOcrPage.LoadZones(fileName, pageNumber) and IOcrPage.LoadZones(stream, pageNumber) to load any single page from a multi-page OCR document into a particular OCR page.

Note on loading zones from a multi-page zone file: If the file does not contain zones data with the correct page number, the engine will not load any zones for this page. After the method returns, any OCR page that did not have zones data will contain zero zones. (the IOcrPage.Zones property conatins 0 items). You can then use IOcrPage.AutoZone if required to re-zone this page.

Use this method to load the zones previously saved into a multi-page zones disk file with the IOcrDocument.SaveZones(fileName) method.

The zones of this page will first be cleared prior to loading the new items.

After this method finishes, you can access the loaded zones in the IOcrPage.Zones property.

To load and save the zones to a .NET stream, use IOcrDocument.SaveZones(stream), IOcrDocument.LoadZones(stream) and IOcrPage.LoadZones(stream, pageNumber).

Saving zones to an external file or a stream could be useful when you are processing forms. For example, you can load one of the forms and automatically find the zones inside it using AutoZone, if the automatic zone detection was not 100 percent satisfactory, you can update the zones in the IOcrPage.Zones collection manually and then save the result with IOcrDocument.SaveZones(fileName). Once the zones are saved. You can now process all similar forms in the following manner:

Add the form page or pages to an OCR document using the Pages collection of IOcrDocument.
Load the zones previously saved for each page using IOcrDocument.LoadZones(fileName).
Skip calling AutoZone and directly call IOcrPage.Recognize or IOcrPage.RecognizeText. This will also speed up the recognition process considerably.

Example

Visual Basic
C#
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

Copy Code

Private Shared Sub LoadSaveZonesExample()
      Dim engineType As OcrEngineType = OcrEngineType.Professional
      Using ocrEngine As IOcrEngine = OcrEngineManager.CreateEngine(engineType, False)
         ocrEngine.Startup(Nothing, Nothing, Nothing, Nothing)
         Using ocrDocument As IOcrDocument = ocrEngine.DocumentManager.CreateDocument()
            ' Add 2 pages
            ocrDocument.Pages.AddPage(Path.Combine(LEAD_VARS.ImagesDir, "Ocr1.tif"), Nothing)
            ocrDocument.Pages.AddPage(Path.Combine(LEAD_VARS.ImagesDir, "Ocr2.tif"), Nothing)

            ' Auto-zone all the pages
            ocrDocument.Pages.AutoZone(Nothing)
            Console.WriteLine("Number of zones after auto-zone:")
            For i As Integer = 0 To ocrDocument.Pages.Count - 1
               Console.WriteLine("  Page {0} has {1} zones.", i, ocrDocument.Pages(i).Zones.Count)
            Next

            ' Save the zones to a disk file
            Dim zonesFileName As String = Path.Combine(LEAD_VARS.ImagesDir, "LoadSaveZonesExample.ozf")
            ocrDocument.SaveZones(zonesFileName)

            ' Clear the zones
            For i As Integer = 0 To ocrDocument.Pages.Count - 1
               ocrDocument.Pages(i).Zones.Clear()
            Next

            ' Show the zones now:
            Console.WriteLine("Number of zones after saving the zones to file and then clear:")
            For i As Integer = 0 To ocrDocument.Pages.Count - 1
               Console.WriteLine("  Page {0} has {1} zones.", i, ocrDocument.Pages(i).Zones.Count)
            Next

            ' Re-load the zones
            ocrDocument.LoadZones(zonesFileName)

            ' Show the zones now:
            ocrDocument.Pages.AutoZone(Nothing)
            Console.WriteLine("Number of zones after loading the zones from file:")
            For i As Integer = 0 To ocrDocument.Pages.Count - 1
               Console.WriteLine("  Page {0} has {1} zones.", i, ocrDocument.Pages(i).Zones.Count)
            Next
         End Using
      End Using
   End Sub

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class

private static void LoadSaveZonesExample()
   {
      OcrEngineType engineType = OcrEngineType.Professional;
      using(IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(engineType, false))
      {
         ocrEngine.Startup(null, null, null, null);
         using(IOcrDocument ocrDocument = ocrEngine.DocumentManager.CreateDocument())
         {
            // Add 2 pages
            ocrDocument.Pages.AddPage(Path.Combine(LEAD_VARS.ImagesDir,"Ocr1.tif"), null);
            ocrDocument.Pages.AddPage(Path.Combine(LEAD_VARS.ImagesDir,"Ocr2.tif"), null);

            // Auto-zone all the pages
            ocrDocument.Pages.AutoZone(null);
            Console.WriteLine("Number of zones after auto-zone:");
            for(int i = 0; i < ocrDocument.Pages.Count; i++)
            {
               Console.WriteLine("  Page {0} has {1} zones.", i, ocrDocument.Pages[i].Zones.Count);
            }

            // Save the zones to a disk file
            string zonesFileName = Path.Combine(LEAD_VARS.ImagesDir,"LoadSaveZonesExample.ozf");
            ocrDocument.SaveZones(zonesFileName);

            // Clear the zones
            for(int i = 0; i < ocrDocument.Pages.Count; i++)
            {
               ocrDocument.Pages[i].Zones.Clear();
            }

            // Show the zones now:
            Console.WriteLine("Number of zones after saving the zones to file and then clear:");
            for(int i = 0; i < ocrDocument.Pages.Count; i++)
            {
               Console.WriteLine("  Page {0} has {1} zones.", i, ocrDocument.Pages[i].Zones.Count);
            }

            // Re-load the zones
            ocrDocument.LoadZones(zonesFileName);

            // Show the zones now:
            ocrDocument.Pages.AutoZone(null);
            Console.WriteLine("Number of zones after loading the zones from file:");
            for(int i = 0; i < ocrDocument.Pages.Count; i++)
            {
               Console.WriteLine("  Page {0} has {1} zones.", i, ocrDocument.Pages[i].Zones.Count);
            }
         }
      }
   }

static class LEAD_VARS
{
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}

private async Task LoadSaveZonesExample()
{
   OcrEngineType engineType = OcrEngineType.Advantage;
   IOcrEngine ocrEngine = OcrEngineManager.CreateEngine(engineType, false);
   ocrEngine.Startup(null, null, String.Empty, Tools.OcrEnginePath);

   IOcrDocument ocrDocument = ocrEngine.DocumentManager.CreateDocument();

   // Add 2 pages
   IOcrPage ocrPage = null;
   using (RasterCodecs codecs = new RasterCodecs())
   {
      StorageFile loadFile = await Tools.AppInstallFolder.GetFileAsync(@"Assets\Ocr1.tif");
      using (RasterImage image = await codecs.LoadAsync(LeadStreamFactory.Create(loadFile)))
         ocrPage = ocrDocument.Pages.AddPage(image, null);

      loadFile = await Tools.AppInstallFolder.GetFileAsync(@"Assets\Ocr2.tif");
      using (RasterImage image = await codecs.LoadAsync(LeadStreamFactory.Create(loadFile)))
         ocrPage = ocrDocument.Pages.AddPage(image, null);
   }

   // Auto-zone all the pages
   ocrDocument.Pages.AutoZone(null);
   Debug.WriteLine("Number of zones after auto-zone:");
   for (int i = 0; i < ocrDocument.Pages.Count; i++)
   {
      Debug.WriteLine("  Page {0} has {1} zones.", i, ocrDocument.Pages[i].Zones.Count);
   }

   // Save the zones to a disk file
   string zonesFileName = "LoadSaveZonesExample.ozf";
   StorageFile saveFile = await Tools.AppLocalFolder.CreateFileAsync(zonesFileName);
   await ocrDocument.SaveZonesAsync(saveFile);

   // Clear the zones
   for (int i = 0; i < ocrDocument.Pages.Count; i++)
   {
      ocrDocument.Pages[i].Zones.Clear();
   }

   // Show the zones now:
   Debug.WriteLine("Number of zones after saving the zones to file and then clear:");
   for (int i = 0; i < ocrDocument.Pages.Count; i++)
   {
      Debug.WriteLine("  Page {0} has {1} zones.", i, ocrDocument.Pages[i].Zones.Count);
   }

   // Re-load the zones
   await ocrDocument.LoadZonesAsync(saveFile);

   // Show the zones now:
   ocrDocument.Pages.AutoZone(null);
   Debug.WriteLine("Number of zones after loading the zones from file:");
   for (int i = 0; i < ocrDocument.Pages.Count; i++)
   {
      Debug.WriteLine("  Page {0} has {1} zones.", i, ocrDocument.Pages[i].Zones.Count);
   }
}

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference

IOcrDocument Interface
IOcrDocument Members
Overload List
IOcrPage.LoadZones(fileName)
IOcrPage.LoadZones(fileName, pageNumber)
IOcrPage.LoadZones(Stream)
IOcrPage.LoadZones(Stream, pageNumber)
IOcrDocument.LoadZones(Stream)
IOcrPage.SaveZones(fileName)
IOcrPage.SaveZones(stream)
IOcrPage.SaveZones(fileName, pageNumber)
IOcrPage.SaveZones(stream, pageNumber)
IOcrDocument.SaveZones(fileName)
IOcrDocument.SaveZones(Stream)
IOcrPageCollection Interface
IOcrZoneCollection Interface
OcrZone Structure
IOcrPage.Recognize
Programming with the LEADTOOLS .NET OCR