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LightControlCommand Class
See Also  Members   Example 



Lightens or darkens all or part of an image by remapping the pixel values. This function is useful for pre-processing images for the purpose of improving barcode recognition results.

Syntax

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

Example

Run the LightControlCommand on an image.

Visual BasicCopy Code
Public Sub LightControlCommandExample()
   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 LowerAverage() As Integer
   ReDim LowerAverage(2)
   Dim Average() As Integer
   ReDim Average(2)
   Dim UpperAverage() As Integer
   ReDim UpperAverage(2)
   LowerAverage(0) = 100 'for blue, gray or yuv
   LowerAverage(1) = 120 'for green
   LowerAverage(2) = 80 'for red
   Average(0) = 150 'for blue, gray or yuv
   Average(1) = 140 'for green
   Average(2) = 128 'for red
   UpperAverage(0) = 190 'for blue, gray or yuv
   UpperAverage(1) = 200 'for green
   UpperAverage(2) = 220 'for red
   Dim command As LightControlCommand = New LightControlCommand(LowerAverage, Average, UpperAverage, LightControlCommandType.Yuv)
   ' change the lightness of 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 LightControlCommandExample() 
{ 
   // 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 
   int[] LowerAverage = new int[3]; 
   int[] Average  = new int[3]; 
   int[] UpperAverage = new int[3]; 
   LowerAverage[0] = 100;  //for blue, gray or yuv 
   LowerAverage[1] = 120;  //for green 
   LowerAverage[2] = 80;   //for red 
   Average[0] = 150;       //for blue, gray or yuv 
   Average[1] = 140;       //for green 
   Average[2] = 128;       //for red 
   UpperAverage[0] = 190;  //for blue, gray or yuv 
   UpperAverage[1] = 200;  //for green 
   UpperAverage[2] = 220;  //for red  
   LightControlCommand command = new LightControlCommand(LowerAverage, Average, UpperAverage, LightControlCommandType.Yuv); 
   // change the lightness of the image. 
   command.Run(image); 
   codecs.Save(image, LeadtoolsExamples.Common.ImagesPath.Path + "Result.jpg", RasterImageFormat.Jpeg, 24); 
 
   RasterCodecs.Shutdown(); 
}

Remarks

  • This class remaps the pixel values of the image across the full range of available pixel values, in order to achieve the values passed in LowerAverage, Average and UpperAverage. For example, call this method for a grayscale image, with Average containing 150, LowerAverage containing 100 and UpperAverage containing 190. The pixels of the image will be remapped so that the new average pixel value for the entire image will be 150, the new average value for those pixels with a value between 0 and the average value for the entire image will be 100, and the new average value for those pixels with a value between the average value for the entire image and the maximum pixel value in the image will be 190.
  • 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 class does not support signed data images.
  • For an example, see the following figure:

  • The following figure shows the same image, after the effect has been applied:

  • To obtain this effect, the following settings were used with the method: LowerAverage = 100
    Average = 255
    UpperAverage = 255
    Type = LightControlCommandType.Yuv
  • This command does not support 32-bit grayscale images.
For more information, refer to Changing Brightness and Contrast.
For more information, refer to Correcting Colors.

Inheritance Hierarchy

System.Object
   Leadtools.ImageProcessing.RasterCommand
      Leadtools.ImageProcessing.Color.LightControlCommand

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