HistogramContrastCommand Class

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Visual Basic
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public class HistogramContrastCommand : Leadtools.ImageProcessing.RasterCommand, Leadtools.ImageProcessing.IRasterCommand

'Declaration

Public Class HistogramContrastCommand 
   Inherits Leadtools.ImageProcessing.RasterCommand
   Implements Leadtools.ImageProcessing.IRasterCommand

'Usage

Dim instance As HistogramContrastCommand

public sealed class HistogramContrastCommand : Leadtools.ImageProcessing.IRasterCommand

@interface LTHistogramContrastCommand : LTRasterCommand

public class HistogramContrastCommand extends RasterCommand

function Leadtools.ImageProcessing.Color.HistogramContrastCommand()

public ref class HistogramContrastCommand : public Leadtools.ImageProcessing.RasterCommand, Leadtools.ImageProcessing.IRasterCommand

This class finds the median brightness of the image, then brightens the pixels with values above the median and darkens the pixels with values below the median. This is more sophisticated (but slower) than the ChangeContrastCommand, which uses the middle possible value (128) rather than finding the actual median.
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;

Run the HistogramContrastCommand on an image and increase its contrast.

C#
Visual Basic
WinRT C#
WinRT JavaScript
Silverlight C#
Silverlight VB

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Imports Leadtools
Imports Leadtools.Codecs
Imports Leadtools.ImageProcessing.Color

   
Public Sub HistogramContrastCommandExample()
   Dim codecs As New RasterCodecs()
   codecs.ThrowExceptionsOnInvalidImages = True
   Dim leadImage As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1.CMP"))

   ' Prepare the command
   Dim command As HistogramContrastCommand = New HistogramContrastCommand
   'Increase the contrast using the histogram by 25 percent of the possible range.
   command.Contrast = 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;

      
public void HistogramContrastCommandExample()
{
   // Load an image
   RasterCodecs codecs = new RasterCodecs();
   codecs.ThrowExceptionsOnInvalidImages = true;
   RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "IMAGE1.CMP"));

   // Prepare the command
   HistogramContrastCommand command = new HistogramContrastCommand();
   //Increase the contrast using the histogram by 25 percent of the possible range.
   command.Contrast = 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";
}

using Leadtools;
using Leadtools.Codecs;
using Leadtools.ImageProcessing.Color;

      
public async Task HistogramContrastCommandExample()
{
   // Load an image
   RasterCodecs codecs = new RasterCodecs();
   codecs.ThrowExceptionsOnInvalidImages = true;
   // Load the image
   string srcFileName = @"Assets\Image1.cmp";
   StorageFile loadFile = await Tools.AppInstallFolder.GetFileAsync(srcFileName);
   RasterImage image = await codecs.LoadAsync(LeadStreamFactory.Create(loadFile));

   // Prepare the command
   HistogramContrastCommand command = new HistogramContrastCommand();
   //Increase the contrast using the histogram by 25 percent of the possible range.
   command.Contrast = 250;
   command.Run(image);

   string destFileName = @"result.jpg";
   StorageFile saveFile = await Tools.AppLocalFolder.CreateFileAsync(destFileName);
   await codecs.SaveAsync(image, LeadStreamFactory.Create(saveFile), RasterImageFormat.Jpeg, 0);
}

using Leadtools;
using Leadtools.Codecs;
using Leadtools.ImageProcessing.Color;
using Leadtools.Examples;

public void HistogramContrastCommandExample(RasterImage image, Stream outStream)
{
   // Prepare the command
   HistogramContrastCommand command = new HistogramContrastCommand();
   //Increase the contrast using the histogram by 25 percent of the possible range.
   command.Contrast = 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 HistogramContrastCommandExample(ByVal image As RasterImage, ByVal outStream As Stream)
   ' Prepare the command
   Dim command As HistogramContrastCommand = New HistogramContrastCommand()
   'Increase the contrast using the histogram by 25 percent of the possible range.
   command.Contrast = 250
   command.Run(image)
   ' Save result image
   Dim codecs As RasterCodecs = New RasterCodecs()
   codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24)
   image.Dispose()
End Sub

Target Platforms

Reference