LightControlCommand Class

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.

Object Model

Syntax

Visual Basic
C#
WinRT C#
WinRT JavaScript
C++

public class LightControlCommand : Leadtools.ImageProcessing.RasterCommand, Leadtools.ImageProcessing.IRasterCommand

'Declaration
 
Public Class LightControlCommand 
   Inherits Leadtools.ImageProcessing.RasterCommand
   Implements Leadtools.ImageProcessing.IRasterCommand

'Usage
 
Dim instance As LightControlCommand

public sealed class LightControlCommand : Leadtools.ImageProcessing.IRasterCommand

function Leadtools.ImageProcessing.Color.LightControlCommand()

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

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.

Example

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

Public Sub LightControlCommandExample()
   Dim codecs As New RasterCodecs()
   codecs.ThrowExceptionsOnInvalidImages = True

   Dim leadImage As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "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, 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

public void LightControlCommandExample()
   {
      // Load an image
      RasterCodecs codecs = new RasterCodecs();
      codecs.ThrowExceptionsOnInvalidImages = true;

      RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "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, Path.Combine(LEAD_VARS.ImagesDir, "Result.jpg"), RasterImageFormat.Jpeg, 24);

   }

static class LEAD_VARS
{
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images";
}

[TestMethod]
public async Task LightControlCommandExample()
{
   // 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
   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);

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

public void LightControlCommandExample(RasterImage image, Stream outStream)
{
   // 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);
   // Save result image
   RasterCodecs codecs = new RasterCodecs();
   codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24);
   image.Dispose();
}

Public Sub LightControlCommandExample(ByVal image As RasterImage, ByVal outStream As Stream)
   ' Prepare the command
   Dim LowerAverage As Integer() = New Integer(2){}
   Dim Average As Integer() = New Integer(2){}
   Dim UpperAverage As Integer() = New Integer(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(image)
   ' Save result image
   Dim codecs As RasterCodecs = New RasterCodecs()
   codecs.Save(image, outStream, RasterImageFormat.Jpeg, 24)
   image.Dispose()
End Sub

Requirements

Target Platforms: Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference