VTK 图像平滑_中值滤波器

1.中值滤波

vtkImageHybridMedian2D实现了对二维图像的中值滤波。其实现原理是，采用一个5x5的模板，逐次将模板中心对应于图像的每个像素上，将模板图像覆盖的像素的中值作为当前像素的输出值。

 1 #include <vtkAutoInit.h>
 2 VTK_MODULE_INIT(vtkRenderingOpenGL);
 3  
 4 #include <vtkSmartPointer.h>
 5 #include <vtkJPEGReader.h>
 6 #include <vtkImageData.h>
 7 #include <vtkImageCast.h>
 8 #include <vtkImageHybridMedian2D.h>
 9 #include <vtkImageActor.h>
10 #include <vtkRenderer.h>
11 #include <vtkRenderWindow.h>
12 #include <vtkRenderWindowInteractor.h>
13 #include <vtkInteractorStyleImage.h>
14  
15 int main(int argc, char* argv[])
16 {
17     vtkSmartPointer<vtkJPEGReader> reader =
18         vtkSmartPointer<vtkJPEGReader>::New();
19     reader->SetFileName("lena.jpg");
20     reader->Update();
21  
22     vtkSmartPointer<vtkImageHybridMedian2D> hybridMedian =
23         vtkSmartPointer<vtkImageHybridMedian2D>::New();
24     hybridMedian->SetInputData(reader->GetOutput());
25     hybridMedian->Update();
26     ///
27     vtkSmartPointer<vtkImageActor> originalActor =
28         vtkSmartPointer<vtkImageActor>::New();
29     originalActor->SetInputData(reader->GetOutput());
30  
31     vtkSmartPointer<vtkImageActor> hybridMedianActor =
32         vtkSmartPointer<vtkImageActor>::New();
33     hybridMedianActor->SetInputData(hybridMedian->GetOutput());
34     /
35     double originalViewport[4] = { 0.0, 0.0, 0.5, 1.0 };
36     double hybridMedianViewport[4] = { 0.5, 0.0, 1.0, 1.0 };
37  
38     vtkSmartPointer<vtkRenderer> originalRenderer =
39         vtkSmartPointer<vtkRenderer>::New();
40     originalRenderer->SetViewport(originalViewport);
41     originalRenderer->AddActor(originalActor);
42     originalRenderer->ResetCamera();
43     originalRenderer->SetBackground(1.0,0,0);
44  
45     vtkSmartPointer<vtkRenderer> hybridMedianRenderer =
46         vtkSmartPointer<vtkRenderer>::New();
47     hybridMedianRenderer->SetViewport(hybridMedianViewport);
48     hybridMedianRenderer->AddActor(hybridMedianActor);
49     hybridMedianRenderer->ResetCamera();
50     hybridMedianRenderer->SetBackground(1.0, 1.0, 1.0);
51     //
52     vtkSmartPointer<vtkRenderWindow> rw =
53         vtkSmartPointer<vtkRenderWindow>::New();
54     rw->AddRenderer(originalRenderer);
55     rw->AddRenderer(hybridMedianRenderer);
56     rw->SetSize(640, 320);
57     rw->Render();
58     rw->SetWindowName("MedianFilterExample");
59  
60     vtkSmartPointer<vtkRenderWindowInteractor> rwi =
61         vtkSmartPointer<vtkRenderWindowInteractor>::New();
62     vtkSmartPointer<vtkInteractorStyleImage> style =
63         vtkSmartPointer<vtkInteractorStyleImage>::New();
64     rwi->SetInteractorStyle(style);
65     rwi->SetRenderWindow(rw);
66     rwi->Initialize();
67     rwi->Start();
68  
69     return 0;
70 }

该类使用非常简单，不需要用户设置任何参数。该方法能够有效的保持图像边缘，并对于椒盐噪声有较好的抑制作用。对于三维图像，则使用vtkImageHybridMedian3D类。

执行结果如下：