失眠网 > VTK修炼之道37：图像平滑_高斯滤波器

VTK修炼之道37：图像平滑_高斯滤波器

时间：2022-11-16 10:18:40

1.高斯滤波

高斯平滑的原理类似于均值滤波。均值滤波模板的系数都是一样的，而高斯平滑则是需要根据像素与模板中心的距离来定义权重。权重的计算方法是采用高斯分布，离中心越远，权重越小。下面是一个利用Gauss滤波进行图像平滑的实例：
#include <vtkAutoInit.h>VTK_MODULE_INIT(vtkRenderingOpenGL);#include <vtkSmartPointer.h>#include <vtkJPEGReader.h>#include <vtkImageCast.h>#include <vtkImageData.h>#include <vtkImageGaussianSmooth.h>#include <vtkImageActor.h>#include <vtkRenderer.h>#include <vtkRenderWindow.h>#include <vtkRenderWindowInteractor.h>#include <vtkInteractorStyleImage.h>//#include <vtkImageEllipsoidSource.h>int main(){vtkSmartPointer<vtkJPEGReader> reader =vtkSmartPointer<vtkJPEGReader>::New();reader->SetFileName("lena.jpg");reader->Update();vtkSmartPointer<vtkImageGaussianSmooth> gaussianSmoothFilter =vtkSmartPointer<vtkImageGaussianSmooth>::New();gaussianSmoothFilter->SetInputConnection(reader->GetOutputPort());gaussianSmoothFilter->SetDimensionality(2);gaussianSmoothFilter->SetRadiusFactor(5); //设置模板范围gaussianSmoothFilter->SetStandardDeviation(3);//正态分布/高斯分布标准差gaussianSmoothFilter->Update();vtkSmartPointer<vtkImageActor> originalActor =vtkSmartPointer<vtkImageActor>::New();originalActor->SetInputData(reader->GetOutput());vtkSmartPointer<vtkImageActor> smoothedActor =vtkSmartPointer<vtkImageActor>::New();smoothedActor->SetInputData(gaussianSmoothFilter->GetOutput());double originalViewport[4] = { 0.0, 0.0, 0.5, 1.0 };double smoothedViewport[4] = { 0.5, 0.0, 1.0, 1.0 };vtkSmartPointer<vtkRenderer> originalRenderer =vtkSmartPointer<vtkRenderer>::New();originalRenderer->SetViewport(originalViewport);originalRenderer->AddActor(originalActor);originalRenderer->ResetCamera();originalRenderer->SetBackground(1.0, 0, 0);vtkSmartPointer<vtkRenderer> gradientMagnitudeRenderer =vtkSmartPointer<vtkRenderer>::New();gradientMagnitudeRenderer->SetViewport(smoothedViewport);gradientMagnitudeRenderer->AddActor(smoothedActor);gradientMagnitudeRenderer->ResetCamera();gradientMagnitudeRenderer->SetBackground(1.0, 1.0, 1.0);vtkSmartPointer<vtkRenderWindow> rw =vtkSmartPointer<vtkRenderWindow>::New();rw->AddRenderer(originalRenderer);rw->AddRenderer(gradientMagnitudeRenderer);rw->SetSize(640, 320);rw->SetWindowName("Smooth by Gaussian");vtkSmartPointer<vtkRenderWindowInteractor> rwi =vtkSmartPointer<vtkRenderWindowInteractor>::New();vtkSmartPointer<vtkInteractorStyleImage> style =vtkSmartPointer<vtkInteractorStyleImage>::New();rwi->SetInteractorStyle(style);rwi->SetRenderWindow(rw);rwi->Initialize();rwi->Start();return 0;}
vtkImageGaussianSmooth类默认是执行三维高斯滤波； SetDimensionality()根据需要设置相应的维数； SetRadiusFactor()用于设置高斯模板的大小，当超出该模板的范围时，系数取0； SetStandardDeviation()用于设置高斯分布函数的标准差。高斯平滑效果如下所示：