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GammaCorrectCommand Class

Summary

Adjusts the intensity of colors in an image by changing the gamma constant that is used to map the intensity values.

Syntax

C#
VB
Java
Objective-C
WinRT C#
C++
public class GammaCorrectCommand : RasterCommand 
@interface LTGammaCorrectCommand : LTRasterCommand 
public class GammaCorrectCommand extends RasterCommand 
function Leadtools.ImageProcessing.Color.GammaCorrectCommand() 

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; 

Example

Run the GammaCorrectCommand on an image and apply gamma correction.

C#
VB
Silverlight C#
Silverlight VB
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Color; 
 
public void GammaCorrectCommandExample() 
{ 
   // Load an image 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.ThrowExceptionsOnInvalidImages = true; 
 
   RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "sample5.cmp")); 
 
   // 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"; 
} 
Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing.Color 
      Leadtools.Examples.Support.SetLicense() 
 
Public Sub GammaCorrectCommandExample() 
   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 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 
using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Color; 
using Leadtools.Examples; 
 
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(); 
} 
Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing.Color 
 
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 

Requirements

Target Platforms

See Also

Reference

GammaCorrectCommand Members

Leadtools.ImageProcessing.Color Namespace

Changing Brightness and Contrast

ChangeIntensityCommand Class

ChangeContrastCommand Class

HistogramContrastCommand Class

StretchIntensityCommand Class

RemapIntensityCommand Class

InvertCommand Class

ChangeHueCommand Class

ChangeSaturationCommand Class

HistogramEqualizeCommand Class

Leadtools.ImageProcessing.FillCommand

HistogramCommand Class

Leadtools.ImageProcessing.Core.WindowLevelCommand

ChannelMixerCommand Class

Leadtools.ImageProcessing.Effects.DeinterlaceCommand

DesaturateCommand Class

Leadtools.ImageProcessing.Effects.EdgeDetectStatisticalCommand

LightControlCommand Class

Leadtools.ImageProcessing.Effects.SmoothEdgesCommand

LocalHistogramEqualizeCommand Class

AddWeightedCommand Class

ColorMergeCommand Class

ColorSeparateCommand Class

MultiplyCommand Class

AutoColorLevelCommand Class

ColorLevelCommand Class

Leadtools.ImageProcessing.Core.CorrelationListCommand

GrayScaleToDuotoneCommand Class

GrayScaleToMultitoneCommand Class

Leadtools.ImageProcessing.Core.HolePunchRemoveCommand

SelectiveColorCommand Class

Leadtools.ImageProcessing.Effects.SkeletonCommand

ChangeHueSaturationIntensityCommand Class

ColorReplaceCommand Class

ColorThresholdCommand Class

MathematicalFunctionCommand Class

SegmentCommand Class

AdaptiveContrastCommand Class

ApplyMathematicalLogicCommand Class

ColorIntensityBalanceCommand Class

Leadtools.ImageProcessing.Core.ColorizeGrayCommand

ContrastBrightnessIntensityCommand Class

Leadtools.ImageProcessing.Core.DigitalSubtractCommand

DynamicBinaryCommand Class

Leadtools.ImageProcessing.Effects.EdgeDetectEffectCommand

Leadtools.ImageProcessing.SpecialEffects.FunctionalLightCommand

Leadtools.ImageProcessing.Core.MultiscaleEnhancementCommand

Leadtools.ImageProcessing.Core.SelectDataCommand

Leadtools.ImageProcessing.Core.ShiftDataCommand

AdjustTintCommand Class

GammaCorrectCommand Class

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Leadtools.ImageProcessing.Color Assembly