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ApplyLinearModalityLookupTableCommand Class
See Also  Members   Example 
Leadtools.ImageProcessing.Core Namespace : ApplyLinearModalityLookupTableCommand Class




Remaps the image pixels by applying a linear transformation described by a rescale slope and an intercept. This class is available in the Document/Medical toolkits only.

Syntax

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

Example

Visual BasicCopy Code
ImageProcessing.Core.ApplyLinearModalityLookupTableCommand
   Public Sub ApplyLinearModalityLookupTableCommandExample()
      RasterCodecs.Startup()
      Dim codecs As New RasterCodecs()
      codecs.ThrowExceptionsOnInvalidImages = True

      Dim leadImage As RasterImage = codecs.Load("C:\Program Files\LEAD Technologies\LEADTOOLS 15\Images\IMAGE2.dic")

      ' Prepare the command
      Dim command As ApplyLinearModalityLookupTableCommand = New ApplyLinearModalityLookupTableCommand
      command.Flags = ModalityLookupTableCommandFlags.None
      command.Intercept = 0.0
      command.Slope = 0.5
      command.Run(leadImage)

      RasterCodecs.Shutdown()
   End Sub
C#Copy Code
ImageProcessing.Core.ApplyLinearModalityLookupTableCommand 
      public void ApplyLinearModalityLookupTableCommandExample() 
      { 
         // Load an image 
         RasterCodecs.Startup(); 
         RasterCodecs codecs = new RasterCodecs(); 
         codecs.ThrowExceptionsOnInvalidImages = true; 
 
         RasterImage image = codecs.Load(@"C:\Program Files\LEAD Technologies\LEADTOOLS 15\Images\IMAGE2.dic"); 
 
         // Prepare the command 
         ApplyLinearModalityLookupTableCommand command = new ApplyLinearModalityLookupTableCommand(); 
         command.Flags     = ModalityLookupTableCommandFlags.None; 
         command.Intercept = 0.0; 
         command.Slope     = 0.5; 
         command.Run(image); 
 
         RasterCodecs.Shutdown(); 
      }

Remarks

  • This class remaps the image pixels by applying a linear transformation described by rescale slope and intercept. In the DICOM world, this is referred to as "applying a linear Modality LookupTable (LookupTable)".
  • This class will remap the image pixels by applying the linear transformation described by the equation:

    Y = mX + b

    m: slope of a straight line, this is also referred to as "Rescale Slope" in the DICOM world.

    b: the y-intercept of a straight line, this is also referred to as "Rescale Intercept" in the DICOM world.

    Y: the resulting pixel value.

    X: the input or original pixel value.
  • This class is helpful in applying what is referred to as a "Linear Modality LookupTable (LookupTable)" in the DICOM world. According to the DICOM standard a "Modality LookupTable (LookupTable)" defines the transformation of manufacturer-dependent pixel values into pixel values, which are manufacturer independent (e.g. Hounsfield units for CT, Optical Density for film digitizers, etc.).
  • This class only works on grayscale images. Using this class for non-grayscale images will generate an error.
  • It is recommended to always set the ModalityLookupTableCommandFlags.UpdateMinMax flag.
  • This class can change the image from signed to unsigned, or from unsigned to signed. This is determined by the values of the resulting image pixels after applying the linear transformation.
  • Only the useful bits in the image are considered. The values are considered as if the image pixel values are normalized, LowBit = 0.
  • For example, let's say the image is:

    BitsPerPixel = 12

    LowBit = 4

    HighBit = 10

    In this case, there are 10-4+1=7 valid bits. This means that there are 128 values to remap.
  • If ModalityLookupTableCommandFlags.AllowRangeExpansion flag is set in Flags property, consider the following example:

    If the dataset has the following attributes:

    BitsPerPixel 16

    HighBit 11

    LowBit 0

    Pixel Range 0 to +4095,

    Unsigned

    The number of bits stored inside the image is 11-0+1 =12.

    If the fIntercept is set to -1024 and fSlope is set to 0, then after applying the rescale slope and intercept:

    Output minimum pixel value = (0 *1 +(-1024))= -1024

    Output maximum pixel value = (4095 *1 +(-1024))= 3071
  • The new pixel value range (-1024 to 3071) can't be represented with the current bits stored (12 bits), which can represent values in the range (-2048 to 2048). In this case the class will change the high bit inside the image handle to be 12 instead of 11 (bits stored becomes 13), which can represent values in the range (-8192 to 8191).
  • Please note that the class won't be able to update the high bit and/or low bit if the number of bits stored was already equal to the image bits per pixel.
  • This class supports 12 and 16-bit grayscale. Support for 12 and 16-bit grayscale is available only in the Document/Medical toolkits.
  • This command does not support 32-bit grayscale images.
For more information, refer to Changing Brightness and Contrast.

Inheritance Hierarchy

System.Object
   Leadtools.ImageProcessing.RasterCommand
      Leadtools.ImageProcessing.Core.ApplyLinearModalityLookupTableCommand

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