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FrequencyFilterCommand Class

Summary

Filters the frequency harmonics data produced by a Fourier Transform method using a range rectangle.

Syntax

WinRT C#

C++

public class FrequencyFilterCommand

Public Class FrequencyFilterCommand

public sealed class FrequencyFilterCommand

function Leadtools.ImageProcessing.Core.FrequencyFilterCommand()

public ref class FrequencyFilterCommand

Remarks

This command is used only when working with Fourier Transform methods.
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 signed images.

For more information, refer to Removing Noise.

Example

Run the FrequencyFilterCommand on an image.

WinRT C#

Imports Leadtools 
Imports Leadtools.Codecs 
Imports Leadtools.ImageProcessing 
Imports Leadtools.ImageProcessing.Core 
 
    
Public Sub FrequencyFilterCommandExample() 
   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 rcRect As LeadRect = New LeadRect(0, 0, leadImage.Width \ 2, leadImage.Height \ 2) 
   Dim FreqCommand As FrequencyFilterCommand = New FrequencyFilterCommand(FTArray, rcRect, _ 
                                                                          FrequencyFilterCommandFlags.InsideX Or _ 
                                                                          FrequencyFilterCommandFlags.OutsideY) 
 
   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

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing; 
using Leadtools.ImageProcessing.Core; 
 
       
public void FrequencyFilterCommandExample() 
{ 
   // 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, Leadtools.RasterSizeFlags.Bicubic); 
 
   sizecommand.Run(image); 
 
   FourierTransformInformation FTArray = new FourierTransformInformation(image); 
   // Apply FFT. 
   FastFourierTransformCommand command = new FastFourierTransformCommand(FTArray, FastFourierTransformCommandFlags.FastFourierTransform |  FastFourierTransformCommandFlags.Gray); 
 
   command.Run(image); 
   LeadRect rcRect = new LeadRect(0, 0, image.Width / 2, image.Height / 2); 
   FrequencyFilterCommand FreqCommand = new FrequencyFilterCommand(FTArray, rcRect, FrequencyFilterCommandFlags.InsideX |   FrequencyFilterCommandFlags.InsideY); 
 
   FastFourierTransformCommand InvCommand = new FastFourierTransformCommand(FTArray, FastFourierTransformCommandFlags.InverseFastFourierTransform |  FastFourierTransformCommandFlags.Gray |   FastFourierTransformCommandFlags.Scale | 
         FastFourierTransformCommandFlags.Both); 
   InvCommand.Run(image); 
 
} 
 
static class LEAD_VARS 
{ 
public const string ImagesDir = @"C:\Users\Public\Documents\LEADTOOLS Images"; 
}

using Leadtools; 
using Leadtools.Codecs; 
using Leadtools.ImageProcessing.Core; 
using Leadtools.ImageProcessing; 
 
       
public async Task FrequencyFilterCommandExample() 
{ 
   // 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 
   // Resize the image to make sure the image's dimensions are power of two. 
   SizeCommand sizecommand = new SizeCommand(256, 256, Leadtools.RasterSizeFlags.Bicubic); 
 
   sizecommand.Run(image); 
 
   FourierTransformInformation FTArray = new FourierTransformInformation(image); 
   // Apply FFT. 
   FastFourierTransformCommand command = new FastFourierTransformCommand(FTArray, FastFourierTransformCommandFlags.FastFourierTransform |  FastFourierTransformCommandFlags.Gray); 
 
   command.Run(image); 
   LeadRect rcRect = LeadRectHelper.Create(0, 0, image.Width / 2, image.Height / 2); 
   FrequencyFilterCommand FreqCommand = new FrequencyFilterCommand(FTArray, rcRect, FrequencyFilterCommandFlags.InsideX |   FrequencyFilterCommandFlags.InsideY); 
 
   FastFourierTransformCommand InvCommand = new FastFourierTransformCommand(FTArray, FastFourierTransformCommandFlags.InverseFastFourierTransform |  FastFourierTransformCommandFlags.Gray |   FastFourierTransformCommandFlags.Scale | 
         FastFourierTransformCommandFlags.Both); 
   InvCommand.Run(image); 
 
}