Question

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，但输出图像始终为黑色。

目前，我正在使用itk :: ImagetoVTKImageFilter（在我的代码中将typedeffed转换为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();

我甚至使用以下代码确认我的VTK ImageData包含255或0的值。

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;
 }

然后我继续做ImageCast以确保数据的类型是unsignedShort。

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

然后我最后使用vtkPNGwriter输出.png文件。请注意，我已尝试输出实际的vtkImageData以及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输出始终为黑色。有谁知道我做错了什么。

Answer 1

为了将来参考，许多PNG阅读器似乎不显示16位数据。因此，我在最后做的无符号短片的演员应该是char。

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

VTKPNGWriter打印出黑色图像？

1 个答案: