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MinimumToZeroCommand Class
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Leadtools.ImageProcessing.Core Namespace : MinimumToZeroCommand Class



Converts grayscale signed image to an unsigned one by shifting all the negative value of the image data, so the minimum negative value will be zero.

Syntax

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

Example

This command will apply 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 MinimumToZeroCommandExample()
   RasterCodecs.Startup()
   Dim codecs As New RasterCodecs()
   codecs.ThrowExceptionsOnInvalidImages = True

   Dim leadImage As RasterImage = codecs.Load(LeadtoolsExamples.Common.ImagesPath.Path + "IMAGE2.dic")

   ' 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)

   RasterCodecs.Shutdown()
End Sub
C#Copy Code
public void MinimumToZeroCommandExample() 
{ 
   // Load an image 
   RasterCodecs.Startup(); 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.ThrowExceptionsOnInvalidImages = true; 
 
   RasterImage image = codecs.Load(LeadtoolsExamples.Common.ImagesPath.Path + "IMAGE2.dic"); 
 
   // 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); 
 
   RasterCodecs.Shutdown(); 
}

Remarks

This command is similar to ConvertSignedToUnsignedCommand. This command automatically determines the value to be shift in order to convert the image to unsigned image.
This command is used usually before the command ZeroToNegativeCommand.
This command updates the Signed property of the RasterImage.
This command also updates the MinValue and MaxValue properties of the RasterImage.
This command does not support 8-bit images.
This command 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.
This command supports signed data images.
This command does not support 32-bit grayscale images.

Inheritance Hierarchy

System.Object
   Leadtools.ImageProcessing.RasterCommand
      Leadtools.ImageProcessing.Core.MinimumToZeroCommand

Requirements

Target Platforms: Microsoft .NET Framework 2.0, Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also