Adjusts the intensity of colors in an image by changing the gamma constant that is used to map the intensity values. Supported in Silverlight, Windows Phone 7

Object Model

Syntax

Visual Basic (Declaration)
Public Class GammaCorrectCommand Inherits Leadtools.ImageProcessing.RasterCommand Implements IRasterCommand

Visual Basic (Usage)	Copy Code
Dim instance As GammaCorrectCommand

C#
public class GammaCorrectCommand : Leadtools.ImageProcessing.RasterCommand, IRasterCommand

C++/CLI
public ref class GammaCorrectCommand : public Leadtools.ImageProcessing.RasterCommand, IRasterCommand

Example

Run the Leadtools.ImageProcessing.Color.GammaCorrectCommand on an image and apply gamma correction.

Visual Basic	Copy Code
Public Sub GammaCorrectCommandExample() Dim codecs As New RasterCodecs() codecs.ThrowExceptionsOnInvalidImages = True Dim leadImage As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Master.jpg")) ' Prepare the command Dim command As GammaCorrectCommand = New GammaCorrectCommand 'Set a gamma value of 2.5. command.Gamma = 250 command.Run(leadImage) codecs.Save(leadImage, Path.Combine(LEAD_VARS.ImagesDir, "Result.jpg"), RasterImageFormat.Jpeg, 24) End Sub Public NotInheritable Class LEAD_VARS Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images" End Class

Visual Basic

Copy Code

Public Sub GammaCorrectCommandExample()
   Dim codecs As New RasterCodecs()
   codecs.ThrowExceptionsOnInvalidImages = True

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

   ' Prepare the command
   Dim command As GammaCorrectCommand = New GammaCorrectCommand
   'Set a gamma value of 2.5.
   command.Gamma = 250

   command.Run(leadImage)
   codecs.Save(leadImage, Path.Combine(LEAD_VARS.ImagesDir, "Result.jpg"), RasterImageFormat.Jpeg, 24)

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 GammaCorrectCommandExample() { // Load an image RasterCodecs codecs = new RasterCodecs(); codecs.ThrowExceptionsOnInvalidImages = true; RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Master.jpg")); // Prepare the command GammaCorrectCommand command = new GammaCorrectCommand(); //Set a gamma value of 2.5. command.Gamma = 250; command.Run(image); codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "Result.jpg"), RasterImageFormat.Jpeg, 24); } static class LEAD_VARS { public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images"; }

Copy Code

public void GammaCorrectCommandExample()
   {
      // Load an image
      RasterCodecs codecs = new RasterCodecs();
      codecs.ThrowExceptionsOnInvalidImages = true;

      RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "Master.jpg"));

      // Prepare the command
      GammaCorrectCommand command  = new GammaCorrectCommand();
      //Set a gamma value of 2.5.
      command.Gamma   = 250;
      command.Run(image);
      codecs.Save(image, Path.Combine(LEAD_VARS.ImagesDir, "Result.jpg"), RasterImageFormat.Jpeg, 24);

   }

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

SilverlightCSharp	Copy Code
public void GammaCorrectCommandExample(RasterImage image, Stream outStream) { // Prepare the command GammaCorrectCommand command = new GammaCorrectCommand(); //Set a gamma value of 2.5. command.Gamma = 250; command.Run(image); // Save result image RasterCodecs codecs = new RasterCodecs(); codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24); image.Dispose(); }

SilverlightCSharp

Copy Code

public void GammaCorrectCommandExample(RasterImage image, Stream outStream)
{
   // Prepare the command
   GammaCorrectCommand command  = new GammaCorrectCommand();
   //Set a gamma value of 2.5.
   command.Gamma   = 250;
   command.Run(image);
   // Save result image
   RasterCodecs codecs = new RasterCodecs();
   codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24);
   image.Dispose();
}

SilverlightVB	Copy Code
Public Sub GammaCorrectCommandExample(ByVal image As RasterImage, ByVal outStream As Stream) ' Prepare the command Dim command As GammaCorrectCommand = New GammaCorrectCommand() 'Set a gamma value of 2.5. command.Gamma = 250 command.Run(image) ' Save result image Dim codecs As RasterCodecs = New RasterCodecs() codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24) image.Dispose() End Sub

SilverlightVB

Copy Code

Public Sub GammaCorrectCommandExample(ByVal image As RasterImage, ByVal outStream As Stream)
   ' Prepare the command
   Dim command As GammaCorrectCommand = New GammaCorrectCommand()
   'Set a gamma value of 2.5.
   command.Gamma = 250
   command.Run(image)
   ' Save result image
   Dim codecs As RasterCodecs = New RasterCodecs()
   codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24)
   image.Dispose()
End Sub

Remarks

Intensity values ideally follow a logarithmic progression, because the eye perceives changes in intensity as being equal when the ratio of change is equal. For example, we would see a change from 0.1 to 0.2 as being equal to a change from 0.2 to 0.4.
Gamma is a standard constant that is used to calculate the progression. For most CRTs the gamma constant is in the range of 2.2 to 2.5.
This class 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 does not support 32-bit grayscale images.

For more information, refer to Changing Brightness and Contrast.

If the image has a LUT and you want to work on the image data, set RasterImage.UseLookupTable to false. Then, after calling the method, reset the UselookupTable property to true, as follows:

            rasterImage.UseLookupTable = false;
            Method(rasterImage);
            
            rasterImage.UseLookupTable = true;

Inheritance Hierarchy

System.Object
Leadtools.ImageProcessing.RasterCommand
Leadtools.ImageProcessing.Color.GammaCorrectCommand

Requirements

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

LEADTOOLS Image Processing (Leadtools.ImageProcessing.Color assembly)	Send comments on this topic. \| Back to Introduction - All Topics \| Help Version 17.0.3.29
GammaCorrectCommand Class
See Also Members

Object Model

Syntax

Example

Remarks

Inheritance Hierarchy

Requirements

See Also

Reference