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AutoColorLevelCommand Class
See Also  Members   Example 



Applies one of several types of automatic color leveling to an image. This function is useful for pre-processing images for the purpose of improving barcode recognition results.

Object Model





Syntax

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

Example

Run the AutoColorLevelCommand on an image.

Visual BasicCopy Code
Public Sub AutoColorLevelCommandExample()
   RasterCodecs.Startup()
   Dim codecs As New RasterCodecs()
   codecs.ThrowExceptionsOnInvalidImages = True

   Dim leadImage As RasterImage = codecs.Load(LeadtoolsExamples.Common.ImagesPath.Path + "Master.jpg")

   ' Prepare the command
   Dim command As AutoColorLevelCommand = New AutoColorLevelCommand
   ' Apply "Auto Leveling" to the image.
   command.Run(leadImage)
   codecs.Save(leadImage, LeadtoolsExamples.Common.ImagesPath.Path + "Result.jpg", RasterImageFormat.Jpeg, 24)

   RasterCodecs.Shutdown()
End Sub
C#Copy Code
public void AutoColorLevelCommandExample() 
{ 
   // Load an image 
   RasterCodecs.Startup(); 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.ThrowExceptionsOnInvalidImages = true; 
 
   RasterImage image = codecs.Load(LeadtoolsExamples.Common.ImagesPath.Path + "Master.jpg"); 
 
   // Prepare the command 
   AutoColorLevelCommand command = new AutoColorLevelCommand(); 
   // Apply "Auto Leveling" to the image. 
   command.Run(image); 
   codecs.Save(image, LeadtoolsExamples.Common.ImagesPath.Path + "Result.jpg", RasterImageFormat.Jpeg, 24); 
 
   RasterCodecs.Shutdown(); 
}

Remarks

  • This command makes the dark values darker and the light values lighter, which automatically enhances shadows and brightens the image. It also maximizes the tonal range of the image. It enhances the contrast and intensity using the image's histogram and a color distribution-based algorithm.
  • The properties in the AutoColorLevelCommand Class will be updated with the MinimumInput, MaximumInput, MinimumOutput, MaximumOutput and Gamma values used by a method for the appropriate channel(s).
  • If you set the AutoColorLevelCommandFlags.NoProcess flag in the Flag property, the ColorLevelCommandData will be updated with the color leveling information used by the AutoColorLevelCommand. If you then pass the updated ColorLevelCommandData structures to the ColorLevelCommand, you will obtain the same result that you would have obtained if you had called the AutoColorLevelCommand with the leveling flag by itself.
  • If the image is a grayscale image, then AutoColorLevelCommandType.Level, AutoColorLevelCommandType.Contrast and AutoColorLevelCommandType.Intensity give identical results. Also the Master, Red, Green and Blue properties will have the same values.
  • As an example, the following figure shows an image before any automatic color leveling has been performed:

    The following figure shows what would happen if you start with the original image and apply the AutoColorLevelCommand using AutoColorLevelCommandType.Level flag.

    The following figure shows what would happen if you start with the original image and apply the AutoColorLevelCommand using AutoColorLevelCommandType.Intensity flag.

    The following figure shows what would happen if you start with the original image and apply the AutoColorLevelCommand using AutoColorLevelCommandType.Contrast flag.

  • 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 signed data images.
  • This command does not support 32-bit grayscale images.
For more information, refer to Correcting Colors.

Inheritance Hierarchy

System.Object
   Leadtools.ImageProcessing.RasterCommand
      Leadtools.ImageProcessing.Color.AutoColorLevelCommand

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