FrequencyFilterCommand Class

Summary

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

Syntax

C++/CLI

Python

public class FrequencyFilterCommand

public ref class FrequencyFilterCommand

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.

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:\LEADTOOLS23\Resources\Images"; 
}