DeskewCommand Class

This command is typically used to automatically straighten scanned images, including bank checks. This command is available in the Document/Medical Toolkits.

This command contains a special algorithm for detecting the skewed checks, To do this add the following flags to Flags property (DeskewCommandFlags.UseCheckDeskew | DeskewCommandFlags.UseLineDetectionCheckDeskew)

• If the Flags property or the flags parameter of the Constructor contains DeskewCommandFlags.ReturnAngleOnly, the command will update the Angle property without rotating the image.
• The calculated rotation is limited to 20 degrees in either direction. This command is intended for images, such as scanned documents, that are mainly horizontal lines of text. The results are less predictable with other types of images.
• This command includes an option to skip deskewing if the angle is very small.
• This command does not support 12 and 16-bit grayscale and 48 and 64-bit color images. If the image is 12 and 16-bit grayscale and 48 and 64-bit color, the command will not throw an exception.
• This command supports signed/unsigned data images.
• This command does not support 32-bit grayscale images.
• This command has been expanded with several flags that can be used to work on bank check images. Different algorithms can be used. For more information, refer to the Remarks section of the DeskewCommand class.

In Silverlight versions of LEADTOOLS, this image processing command will fail if the image data for the RasterImage object is stored internally using a Silverlight WriteableBitmap object. For more information, refer to Image Processing Command Limitations in Silverlight.

Runs the DeskewCommand on an image and straightens it.

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

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Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.ImageProcessing.Core

   
Public Sub DeskewCommandExample()
   Dim codecs As New RasterCodecs()
   codecs.ThrowExceptionsOnInvalidImages = True
   Dim leadImage As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Clean.tif"))

   ' Prepare the command
   Dim command As DeskewCommand = New DeskewCommand
   'Deskew the image.
   command.Flags = DeskewCommandFlags.DeskewImage Or DeskewCommandFlags.DoNotFillExposedArea

   command.Run(leadImage)

End Sub

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

using Leadtools;
using Leadtools.Codecs;
using Leadtools.ImageProcessing.Core;

      
public void DeskewCommandExample()
{
   // Load an image
   RasterCodecs codecs = new RasterCodecs();
   codecs.ThrowExceptionsOnInvalidImages = true;
   RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Clean.tif"));

   // Prepare the command
   DeskewCommand command = new DeskewCommand();
   //Deskew the image.
   command.Flags = DeskewCommandFlags.DeskewImage | DeskewCommandFlags.DoNotFillExposedArea;
   command.Run(image);

}

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

function DeskewCommandExample()
{
   var codecs = new Leadtools.Codecs.RasterCodecs();
   codecs.throwExceptionsOnInvalidImages = true;

   // Load the image
   var srcFileName = "Assets\\clean.tif";
   return Tools.AppInstallFolder().getFileAsync(srcFileName).then(function (loadFile) {
      return codecs.loadAsync(Leadtools.LeadStreamFactory.create(loadFile));
   }).then(function (image) {
      // Prepare the command
      with (Leadtools.ImageProcessing.Core) {
         var command = new DeskewCommand();
         //Deskew the image.
         command.flags = DeskewCommandFlags.deskewImage | DeskewCommandFlags.doNotFillExposedArea;
         command.run(image);
      }
   });
}

using Leadtools;
using Leadtools.Codecs;
using Leadtools.ImageProcessing.Core;

      
public async Task DeskewCommandExample()
{
   // Load an image
   RasterCodecs codecs = new RasterCodecs();
   codecs.ThrowExceptionsOnInvalidImages = true;
   // Load the image
   string srcFileName = @"Assets\Clean.tif";
   StorageFile loadFile = await Tools.AppInstallFolder.GetFileAsync(srcFileName);
   RasterImage image = await codecs.LoadAsync(LeadStreamFactory.Create(loadFile));

   // Prepare the command
   DeskewCommand command = new DeskewCommand();
   //Deskew the image.
   command.Flags = DeskewCommandFlags.DeskewImage | DeskewCommandFlags.DoNotFillExposedArea;
   command.Run(image);

}

using Leadtools;
using Leadtools.Examples;
using Leadtools.Codecs;
using Leadtools.ImageProcessing.Core;

public void DeskewCommandExample(RasterImage image, Stream outStream)
{
   // Prepare the command
   DeskewCommand command = new DeskewCommand();
   //Deskew the image.
   command.Flags = DeskewCommandFlags.DeskewImage | DeskewCommandFlags.DoNotFillExposedArea;
   command.Run(image);
   // Save result image
   RasterCodecs codecs = new RasterCodecs();
   codecs.Save(image, outStream, RasterImageFormat.CcittGroup4, 1);
   image.Dispose();
}

Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.ImageProcessing.Core

Public Sub DeskewCommandExample(ByVal image As RasterImage, ByVal outStream As Stream)
   ' Prepare the command
   Dim command As DeskewCommand = New DeskewCommand()
   'Deskew the image.
   command.Flags = DeskewCommandFlags.DeskewImage Or DeskewCommandFlags.DoNotFillExposedArea
   command.Run(image)
   ' Save result image
   Dim codecs As RasterCodecs = New RasterCodecs()
   codecs.Save(image, outStream, RasterImageFormat.CcittGroup4, 1)
   image.Dispose()
End Sub

Target Platforms

Reference

DeskewCommand Members
Leadtools.ImageProcessing.Core Namespace
Introduction to Image Processing With LEADTOOLS
DespeckleCommand Class
WindowLevelCommand Class
ApplyTransformationParametersCommand Class
GetRegistrationMarksCenterMass Method
GetTransformationParameters Method
IsRegistrationMark Method
SearchRegistrationMarksCommand Class