VTKPNGWriter打印黑色图像

VTKPNGWriter printing out black images?

本文关键字：图像 黑色 打印 VTKPNGWriter      更新时间：2023-10-16

我正在使用ITK进行一些图像处理，然后使用VTK以。png格式打印结果，但是输出图像始终是黑色的。

目前，我正在使用itk::ImagetoVTKImageFilter(在我的代码中定义为ITKtoVTKFilterType)将itk::Image转换为vtk::vtkImageData。

ITKtoVTKFilterType::Pointer itk2vtkGray = ITKtoVTKFilterType::New();
itk2vtkGray->SetInput(grayBinary);  //grayBinary is of type itk::Image<unsigned short, 2>
itk2vtkGray->Update();
vtkSmartPointer<vtkImageData> grayVTK = vtkSmartPointer<vtkImageData>::New();
grayVTK->SetExtent(extent);
grayVTK->SetSpacing(m_spacing);
grayVTK->SetScalarTypeToUnsignedShort();
grayVTK->SetNumberOfScalarComponents(1);
grayVTK->AllocateScalars();
grayVTK->DeepCopy(static_cast<vtkImageData*>(itk2vtkGray->GetOutput()));
//grayVTK = itk2vtkGray->GetOutput();

我甚至已经确认我的VTK ImageData包含255或0的值使用以下代码。

int *dims = grayVTK->GetDimensions();
std::cout << "Dims: " << " x: " << dims[0] << " y: " << dims[1] << " z: " << dims[2] << std::endl;
std::cout << "Number of points: " << grayVTK->GetNumberOfPoints() << std::endl;
std::cout << "Number of cells: " << grayVTK->GetNumberOfCells() << std::endl;
for (int y = 0; y < dims[1]; y++)
{        
     for (int x = 0; x < dims[0]; x++)
     {
         unsigned short *pixel = static_cast<unsigned short*>(grayVTK->GetScalarPointer(x,y,0));
         std::cout << "PIXEL LOC/VAL "<< y*dims[0] + x << " " << pixel[0] <<std::endl;
     }
     std::cout << std::endl;
 }

然后我继续执行ImageCast以确保数据的类型为unsignedShort。

vtkSmartPointer<vtkImageCast> cast2 = vtkSmartPointer<vtkImageCast>::New();
cast2->SetInput(grayVTK);
cast2->SetOutputScalarTypeToUnsignedShort();
cast2->ClampOverflowOn();
cast2->Update();

然后最后我使用vtkPNGwriter输出。png文件。注意，我已经尝试输出实际的vtkImageData以及来自ImageCastFilter的输出。

vtkSmartPointer<vtkPNGWriter> writer =
vtkSmartPointer<vtkPNGWriter>::New();
writer->SetFileName(filename.toStdString().c_str());
writer->SetInputConnection(cast2->GetOutputPort());
//writer->SetInput(grayVTK); I have tried to method as well but to no success
writer->Write();

但是，.png输出总是黑色的。有谁知道我做错了什么吗?

对于将来的参考，似乎许多PNG阅读器不显示16位数据。因此，我在最后对unsigned short进行的强制转换应该是char.

vtkSmartPointer<vtkImageCast> cast2 = vtkSmartPointer<vtkImageCast>::New();
cast2->SetInput(grayVTK);
cast2->SetOutputScalarTypeToChar();
cast2->ClampOverflowOn();
cast2->Update();
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