ITK学习笔记——中值滤波和均值滤波

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均值滤波和和中值滤波都可以起到平滑图像，虑去噪声的功能。
均值滤波采用线性的方法，平均整个窗口范围内的像素值，均值滤波本身存在着固有的缺陷，即它不能很好地保护图像细节，在图像去噪的同时也破坏了图像的细节部分，从而使图像变得模糊，不能很好地去除噪声点。均值滤波对高斯噪声表现较好，对椒盐噪声表现较差。
中值滤波采用非线性的方法，它在平滑脉冲噪声方面非常有效,同时它可以保护图像尖锐的边缘，选择适当的点来替代污染点的值，所以处理效果好，对椒盐噪声表现较好，对高斯噪声表现较差。

中值滤波：

#include "itkImage.h"
#include "itkImageFileReader.h"
#include "itkMedianImageFilter.h"
#include "itkSubtractImageFilter.h"#include "itksys/SystemTools.hxx"
#include <sstream>#include "QuickView.h"int main(int argc, char * argv[])
{std::string inputFilename = "C:/input/Lenna.jpeg";typedef itk::Image<float, 2 >                         ImageType;typedef itk::ImageFileReader<ImageType>               ReaderType;typedef itk::MedianImageFilter<ImageType, ImageType > FilterType;typedef itk::SubtractImageFilter<ImageType>           SubtractType;ReaderType::Pointer reader = ReaderType::New();reader->SetFileName( inputFilename );FilterType::Pointer medianFilter = FilterType::New();FilterType::InputSizeType radius;radius.Fill(2);medianFilter->SetRadius(radius);medianFilter->SetInput( reader->GetOutput() );SubtractType::Pointer diff = SubtractType::New();diff->SetInput1(reader->GetOutput());diff->SetInput2(medianFilter->GetOutput());QuickView viewer;viewer.AddImage(reader->GetOutput(),true,itksys::SystemTools::GetFilenameName(inputFilename));  std::stringstream desc;desc << "MedianImageFilter, radius = " << radius;viewer.AddImage(medianFilter->GetOutput(),true,desc.str());  std::stringstream desc2;desc2 << "Original - Median";viewer.AddImage(diff->GetOutput(),true,desc2.str());  viewer.Visualize();return EXIT_SUCCESS;
}

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由于读取没用RGB格式，所以会自动转化为灰度图。

均值滤波：

#include "itkImage.h"
#include "itkImageFileReader.h"
#include "itkMeanImageFilter.h"
#include "itkSubtractImageFilter.h"#include "QuickView.h"int main(int argc, char * argv[])
{typedef itk::Image< unsigned char, 2 >                UnsignedCharImageType;typedef itk::Image< float, 2 >                        FloatImageType;typedef itk::ImageFileReader< UnsignedCharImageType > ReaderType;typedef itk::MeanImageFilter<UnsignedCharImageType, UnsignedCharImageType > filterType;typedef itk::SubtractImageFilter<UnsignedCharImageType, UnsignedCharImageType, FloatImageType>           SubtractType;ReaderType::Pointer reader = ReaderType::New();reader->SetFileName( "C:/input/Lenna.jpeg" );filterType::Pointer meanFilter = filterType::New();meanFilter->SetInput( reader->GetOutput() );SubtractType::Pointer diff = SubtractType::New();diff->SetInput1(reader->GetOutput());diff->SetInput2(meanFilter->GetOutput());QuickView viewer;viewer.AddImage(reader->GetOutput(),true,itksys::SystemTools::GetFilenameName("C:/input/Lenna.jpeg"));  std::stringstream desc;desc << "Mean";viewer.AddImage(meanFilter->GetOutput(),true,desc.str());  std::stringstream desc2;desc2 << "Original - Mean";viewer.AddImage(diff->GetOutput(),true,desc2.str());  viewer.Visualize();return EXIT_SUCCESS;
}

在这里插入图片描述