GammaCorrectExtendedCommand Class

Summary

Adjusts the intensity of colors in an image by changing the gamma constant that is used to map the intensity values. Either of two different color spaces can be specified.

Syntax

Objective-C

C++

Java

public class GammaCorrectExtendedCommand : RasterCommand

Public Class GammaCorrectExtendedCommand  
   Inherits RasterCommand

@interface LTGammaCorrectExtendedCommand : LTRasterCommand

public class GammaCorrectExtendedCommand extends RasterCommand

public ref class GammaCorrectExtendedCommand : public RasterCommand

Remarks

This command is like the GammaCorrectCommand method, but has been extended to allow the specification of the colorspace to be used.
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 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 does not support 32-bit grayscale images.

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;

Example

Run the GammaCorrectExtendedCommand on an image.

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Color; 
 
public void GammaCorrectExtendedCommandExample() 
{ 
   // Load an image 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.ThrowExceptionsOnInvalidImages = true; 
 
   RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "sample5.cmp")); 
 
   // Prepare the command 
   GammaCorrectExtendedCommand command = new GammaCorrectExtendedCommand(); 
 
   // Apply gamma effect on image using the YUV color space and gamma value of 2.50 
   command.Gamma = 250; 
   command.Type = GammaCorrectExtendedCommandType.YuvSpace; 
   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"; 
}

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing.Color 
 
Public Sub GammaCorrectExtendedCommandExample() 
   Dim codecs As New RasterCodecs() 
   codecs.ThrowExceptionsOnInvalidImages = True 
 
   Dim leadImage As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "sample5.cmp")) 
 
   ' Prepare the command 
   Dim command As New GammaCorrectExtendedCommand 
 
   ' Apply gamma effect on image using the YUV color space and gamma value of 2.50 
   command.Gamma = 250 
   command.Type = GammaCorrectExtendedCommandType.YuvSpace 
   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#[Silverlight C# Example] 
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Examples; 
 
public void GammaCorrectExtendedCommandExample(RasterImage image, Stream outStream) 
{ 
   // Prepare the command 
   GammaCorrectExtendedCommand command = new GammaCorrectExtendedCommand(); 
 
   // Apply gamma effect on image using the YUV color space and gamma value of 2.50 
   command.Gamma = 250; 
   command.Type = GammaCorrectExtendedCommandType.YuvSpace; 
   command.Run(image); 
 
   // Save result image 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24); 
   image.Dispose(); 
} 
vb[Silverlight VB Example] 
Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing.Color 
 
Public Sub GammaCorrectExtendedCommandExample(ByVal image As RasterImage, ByVal outStream As Stream) 
   ' Prepare the command 
   Dim command As GammaCorrectExtendedCommand = New GammaCorrectExtendedCommand() 
 
   ' Apply gamma effect on image using the YUV color space and gamma value of 2.50 
   command.Gamma = 250 
   command.Type = GammaCorrectExtendedCommandType.YuvSpace 
   command.Run(image) 
 
   ' Save result image 
   Dim codecs As RasterCodecs = New RasterCodecs() 
   codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24) 
   image.Dispose() 
End Sub