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FrequencyFilterMaskCommand Class

Summary

Creates a mask filter to remove specific frequency components from the image. This command is available in the Imaging Pro and above toolkits.

Syntax

WinRT C#

C++

public class FrequencyFilterMaskCommand

Public Class FrequencyFilterMaskCommand

public sealed class FrequencyFilterMaskCommand

function Leadtools.ImageProcessing.Core.FrequencyFilterMaskCommand()

public ref class FrequencyFilterMaskCommand

Remarks

This command is used only when you are dealing with Fourier Transform methods.
The MaskImage will be treated as grayscale image. The (0,0) frequency located in mask image center; positive X harmonics located in the right half of the mask image and positive Y harmonics located in the lower half of the mask image. Mask image's dimensions must be equal to Data's dimensions.
This command does not support 12 and 16-bit grayscale and 48 and 64-bit color images. If the image is 12 and 16-bit grayscale and 48 and 64-bit color, the command will not threw an exception.
This command does not support 32-bit grayscale images.
This command does not support signed images.

For more information, refer to Removing Noise.

Example

Run the FrequencyFilterMaskCommand on an image.

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Core; 
 
public void FrequencyFilterMaskCommandExample() 
{ 
   // Load an image 
   RasterCodecs codecs = new RasterCodecs(); 
   codecs.ThrowExceptionsOnInvalidImages = true; 
 
   RasterImage image = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, @"ImageProcessingDemo\FourierTransform.jpg")); 
 
   // Prepare the command 
   // Resize the image to make sure the image's dimensions are power of two. 
   SizeCommand sizecommand = new SizeCommand(256, 256, RasterSizeFlags.Bicubic); 
 
   sizecommand.Run(image); 
 
   FourierTransformInformation FTArray = new FourierTransformInformation(image); 
   // Apply FFT. 
   FastFourierTransformCommand command = new FastFourierTransformCommand(FTArray, FastFourierTransformCommandFlags.FastFourierTransform | FastFourierTransformCommandFlags.Gray); 
   command.Run(image); 
 
   FrequencyFilterMaskCommand FreqCommand = new FrequencyFilterMaskCommand(image, FTArray, false); 
 
 
 
   FastFourierTransformCommandFlags flags = FastFourierTransformCommandFlags.InverseFastFourierTransform | FastFourierTransformCommandFlags.Gray | FastFourierTransformCommandFlags.Scale | FastFourierTransformCommandFlags.Both; 
   FastFourierTransformCommand InvCommand = new FastFourierTransformCommand(FTArray, flags); 
   InvCommand.Run(image); 
 
} 
 
static class LEAD_VARS 
{ 
   public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images"; 
}

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Core 
      Leadtools.Examples.Support.SetLicense() 
 
Public Sub FrequencyFilterMaskCommandExample() 
   Dim codecs As New RasterCodecs() 
   codecs.ThrowExceptionsOnInvalidImages = True 
 
   Dim leadImage As RasterImage = codecs.Load(Path.Combine(LEAD_VARS.ImagesDir, "ImageProcessingDemo\\FourierTransform.jpg")) 
 
   ' Prepare the command 
   ' Resize the image to make sure the image's dimensions are power of two. 
   Dim sizecommand As SizeCommand = New SizeCommand(256, 256, RasterSizeFlags.Bicubic) 
 
   sizecommand.Run(leadImage) 
 
   Dim FTArray As FourierTransformInformation = New FourierTransformInformation(leadImage) 
   ' Apply FFT. 
   Dim command As FastFourierTransformCommand = New FastFourierTransformCommand(FTArray, 
                                                                                FastFourierTransformCommandFlags.FastFourierTransform Or 
                                                                                FastFourierTransformCommandFlags.Gray) 
 
   command.Run(leadImage) 
 
   Dim FreqCommand As FrequencyFilterMaskCommand = New FrequencyFilterMaskCommand(leadImage, FTArray, False) 
   Dim InvCommand As FastFourierTransformCommand = New FastFourierTransformCommand(FTArray, 
                                                                                   FastFourierTransformCommandFlags.InverseFastFourierTransform Or 
                                                                                   FastFourierTransformCommandFlags.Gray Or 
                                                                                   FastFourierTransformCommandFlags.Scale Or 
                                                                                   FastFourierTransformCommandFlags.Both) 
 
   InvCommand.Run(leadImage) 
 
End Sub 
 
Public NotInheritable Class LEAD_VARS 
   Public Const ImagesDir As String = "C:\Users\Public\Documents\LEADTOOLS Images" 
End Class