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ZeroToNegativeCommand Class
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Leadtools.ImageProcessing.Core Namespace : ZeroToNegativeCommand Class



Converts a grayscale unsigned image to a signed image by shifting the image data to the negative side by the amount specified by the user. Supported in Silverlight, Windows Phone 7

Object Model

ZeroToNegativeCommand Class

Syntax

Visual Basic (Declaration) 
Public Class ZeroToNegativeCommand 
   Inherits Leadtools.ImageProcessing.RasterCommand
   Implements IRasterCommand 
Visual Basic (Usage)Copy Code
Dim instance As ZeroToNegativeCommand
C# 
public class ZeroToNegativeCommand : Leadtools.ImageProcessing.RasterCommand, IRasterCommand 
C++/CLI 
public ref class ZeroToNegativeCommand : public Leadtools.ImageProcessing.RasterCommand, IRasterCommand 

Example

This command will apply Leadtools.ImageProcessing.Core.MultiscaleEnhancementCommand on a signed image, but since MultiscaleEnhancementCommand doesn't support signed images, we will convert the image to unsigned image, apply the effect, and then convert it back to signed image.

Visual BasicCopy Code
Public Sub ZeroToNegativeCommandExample()
   Dim codecs As New RasterCodecs()
   codecs.ThrowExceptionsOnInvalidImages = True

   Dim leadImage As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "ImageProcessingDemo\Beauty16.jpg"))

   ' Prepare the command
   ' Convert the image to unsigned image by shifting the negative values to become positive.
   Dim MinToZCommand As MinimumToZeroCommand = New MinimumToZeroCommand
   MinToZCommand.Run(leadImage)

   ' Apply multiscale enhancement
   Dim MultiScaleCommand As MultiscaleEnhancementCommand = New MultiscaleEnhancementCommand(2000, 4, -1, 0, 0, MultiscaleEnhancementCommandType.Gaussian, MultiscaleEnhancementCommandFlags.EdgeEnhancement)

   ' Convert the image back to signed by shifting the same amount in the negative side.
   Dim command As ZeroToNegativeCommand = New ZeroToNegativeCommand
   command.MinimumInput = -32767
   command.MaximumInput = 32766
   command.MinimumOutput = 0
   command.MaximumOutput = 65535
   command.ShiftAmount = MinToZCommand.ShiftAmount
   command.Run(leadImage)

End Sub

Public NotInheritable Class LEAD_VARS
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images"
End Class
C#Copy Code
public void ZeroToNegativeCommandExample()
   {
      // Load an image
      RasterCodecs codecs = new RasterCodecs();
      codecs.ThrowExceptionsOnInvalidImages = true;

      RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, @"ImageProcessingDemo\Beauty16.jpg"));

      // Prepare the command
      // Convert the image to unsigned image by shifting the negative values to become positive.
      MinimumToZeroCommand MinToZCommand = new MinimumToZeroCommand();
      MinToZCommand.Run(image); 

      // Apply multiscale enhancement
      MultiscaleEnhancementCommand MultiScaleCommand = new MultiscaleEnhancementCommand(2000, 4, -1, 0, 0, MultiscaleEnhancementCommandType.Gaussian, MultiscaleEnhancementCommandFlags.EdgeEnhancement);

      // Convert the image back to signed by shifting the same amount in the negative side.
      ZeroToNegativeCommand command = new ZeroToNegativeCommand();
      command.MinimumInput  = -32767;
      command.MaximumInput  = 32766;
      command.MinimumOutput = 0;
      command.MaximumOutput = 65535;
      command.ShiftAmount   = MinToZCommand.ShiftAmount;
      command.Run(image);

   }

static class LEAD_VARS
{
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}
SilverlightCSharpCopy Code
public void ZeroToNegativeCommandExample(RasterImage image, Stream outStream)
{
   // Prepare the command
   // Convert the image to unsigned image by shifting the negative values to become positive.
   MinimumToZeroCommand MinToZCommand = new MinimumToZeroCommand();
   MinToZCommand.Run(image); 
   // Apply multiscale enhancement
   MultiscaleEnhancementCommand MultiScaleCommand = new MultiscaleEnhancementCommand(2000, 4, -1, 0, 0, MultiscaleEnhancementCommandType.Gaussian, MultiscaleEnhancementCommandFlags.EdgeEnhancement);

   // Convert the image back to signed by shifting the same amount in the negative side.
   ZeroToNegativeCommand command = new ZeroToNegativeCommand();
   command.MinimumInput  = -32767;
   command.MaximumInput  = 32766;
   command.MinimumOutput = 0;
   command.MaximumOutput = 65535;
   command.ShiftAmount   = MinToZCommand.ShiftAmount;
   command.Run(image);

   // Save result image
   RasterCodecs codecs = new RasterCodecs();
   codecs.Save(image, outStream, RasterImageFormat.DicomGray, image.BitsPerPixel);
   image.Dispose();
}
SilverlightVBCopy Code
Public Sub ZeroToNegativeCommandExample(ByVal image As RasterImage, ByVal outStream As Stream)
   ' Prepare the command
   ' Convert the image to unsigned image by shifting the negative values to become positive.
   Dim MinToZCommand As MinimumToZeroCommand = New MinimumToZeroCommand()
   MinToZCommand.Run(image)
   ' Apply multiscale enhancement
   Dim MultiScaleCommand As MultiscaleEnhancementCommand = New MultiscaleEnhancementCommand(2000, 4, -1, 0, 0, MultiscaleEnhancementCommandType.Gaussian, MultiscaleEnhancementCommandFlags.EdgeEnhancement)

   ' Convert the image back to signed by shifting the same amount in the negative side.
   Dim command As ZeroToNegativeCommand = New ZeroToNegativeCommand()
   command.MinimumInput = -32767
   command.MaximumInput = 32766
   command.MinimumOutput = 0
   command.MaximumOutput = 65535
   command.ShiftAmount = MinToZCommand.ShiftAmount
   command.Run(image)

   ' Save result image
   Dim codecs As RasterCodecs = New RasterCodecs()
   codecs.Save(image, outStream, RasterImageFormat.DicomGray, image.BitsPerPixel)
   image.Dispose()
End Sub

Remarks

This command is similar to Leadtools.ImageProcessing.Core.ConvertUnsignedToSignedCommand. However, MinimumToZeroCommand updates MinimumToZeroCommand.ShiftAmount with the value by which the intensity values were shifted. The updated MinimumToZeroCommand.ShiftAmount value can be passed to ZeroToNegativeCommand to convert the image back to signed (i.e. after using image processing command that works in unsigned 12-16 bit grayscale image).
MinimumToZeroCommand and ZeroToNegativeCommand are most often used in concert with one or more image processing or analysis commands. MinimumToZeroCommand converts signed data to unsigned data, in preparation for image processing or analysis commands that work on unsigned image data. After the image processing or analysis is performed, ZeroToNegativeCommand can be used to converts the unsigned data back to signed data.

This command is used usually after the command MinimumToZeroCommand.

This command updates the Leadtools.RasterImage.Signed property of the Leadtools.RasterImage.

This command also updates the Leadtools.RasterImage.MinValue and Leadtools.RasterImage.MaxValue properties of the Leadtools.RasterImage.

This command supports signed data images and supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available only in the Document/Medical toolkits. However, this command does not support 8-bit images.

This command does not support 32-bit grayscale images.

Inheritance Hierarchy

System.Object
   Leadtools.ImageProcessing.RasterCommand
      Leadtools.ImageProcessing.Core.ZeroToNegativeCommand

Requirements

Target Platforms: Silverlight 3.0, Windows XP, Windows Server 2003 family, Windows Server 2008 family, Windows Vista, Windows 7, MAC OS/X (Intel Only)

See Also