ITK 实例3 OTSU算法对PNG图像进行单阈值二维分割

 1 #include "itkOtsuThresholdImageFilter.h"//Otsu分割头文件
 2 #include "itkImage.h"
 3 #include "itkImageFileReader.h"
 4 #include "itkImageFileWriter.h"
 5  
 6 int main( int argc, char * argv[] )
 7 {
 8   /*if( argc < 5 )
 9     {
10     std::cerr << "Usage: " << argv[0];
11     std::cerr << " inputImageFile outputImageFile ";
12     std::cerr << " insideValue    outsideValue   "  << std::endl;
13     return EXIT_FAILURE;
14     }*/
15  
16   //确定作为输入和输出图像的像素类型
17   typedef  unsigned char  InputPixelType;
18   typedef  unsigned char  OutputPixelType;
19   const unsigned int      Dimension = 2;
20  //使用输入输出图像的像素类型和维来定义它们的图像类型
21   typedef itk::Image< InputPixelType,  Dimension >   InputImageType;
22   typedef itk::Image< OutputPixelType, Dimension >   OutputImageType;
23   //使用上面定义的输入输出图像的类型对滤波器类型进行实例化
24   typedef itk::OtsuThresholdImageFilter<InputImageType, OutputImageType >  FilterType;
25   //对一个 itk::ImageFileReader 类也进行实例化以便从文件中读取图像数据
26   typedef itk::ImageFileReader< InputImageType >  ReaderType;
27   
28   typedef itk::ImageFileWriter< OutputImageType >  WriterType;
29   //调用 New( ) 方式创建滤波器和 reader 并将结果指向 itk::Smartpointers 
30   ReaderType::Pointer reader = ReaderType::New();
31   FilterType::Pointer filter = FilterType::New();
32   WriterType::Pointer writer = WriterType::New();
33  
34   //由 reader 得到的图像作为输入传递给 OtsuThresholdImageFilter
35   reader->SetFileName("BrainProtonDensitySlice.png");
36   filter->SetInput(reader->GetOutput());
37   writer->SetInput( filter->GetOutput() );
38  
39   //outsideValue:给定阈值的上下限范围之外的像素的亮度值
40   //insideValue:给定阈值的上下限范围之内的像素的亮度值
41   const OutputPixelType outsideValue = atoi( "0" );//范围之外设置为纯黑
42   const OutputPixelType insideValue  = atoi( "255" );//范围之内设置为纯白
43  
44   /*用 SetOutsideValue() 方式定义指向那些亮度值在给定阈值的上下限范围之外的像素的
45   亮度值，用 SetInsideValue() 方式定义指向那些亮度值在给定阈值的上下限范围之内的像素的
46   亮度值*/
47   filter->SetOutsideValue( outsideValue );
48   filter->SetInsideValue(  insideValue  );
49   
50   try
51     {
52     filter->Update();
53     }
54   catch( itk::ExceptionObject & excp )
55     {
56     std::cerr << "Exception thrown " << excp << std::endl;
57     }
58   
59   //由滤波器内部计算得到的阈值。为了做到这些我们调用 GetThreshold 方式
60   int threshold = filter->GetThreshold();
61   std::cout << "Threshold = " << threshold << std::endl;
62   
63   writer->SetFileName( "BrainProtonDensitySlice_OTSU2.png" );
64   try
65     {
66     writer->Update();
67     }
68   catch( itk::ExceptionObject & excp )
69     {
70     std::cerr << "Exception thrown " << excp << std::endl;
71     }
72  
73   return EXIT_SUCCESS;
74 }