RescaleAnImage
VTKExamples/Cxx/ImageProcessing/RescaleAnImage
Code¶
RescaleAnImage.cxx
#include <vtkImageData.h> #include <vtkImageShiftScale.h> #include <vtkMath.h> #include <vtkSmartPointer.h> static void CreateImage(vtkImageData* const image); int main(int argc, char *argv[]) { vtkSmartPointer<vtkImageData> image = vtkSmartPointer<vtkImageData>::New(); CreateImage(image); vtkSmartPointer<vtkImageShiftScale> shiftScaleFilter = vtkSmartPointer<vtkImageShiftScale>::New(); shiftScaleFilter->SetOutputScalarTypeToUnsignedChar(); #if VTK_MAJOR_VERSION <= 5 shiftScaleFilter->SetInputConnection(image->GetProducerPort()); #else shiftScaleFilter->SetInputData(image); #endif shiftScaleFilter->SetShift(-1.0f * image->GetScalarRange()[0]); // brings the lower bound to 0 float oldRange = image->GetScalarRange()[1] - image->GetScalarRange()[0]; std::cout << "Old range: [" << image->GetScalarRange()[0] << ", " << image->GetScalarRange()[1] << "]" << std::endl; std::cout << "Old range magnitude: " << oldRange << std::endl; float newRange = 255; // We want the output [0,255] shiftScaleFilter->SetScale(newRange/oldRange); shiftScaleFilter->Update(); std::cout << "New range: [" << shiftScaleFilter->GetOutput()->GetScalarRange()[1] << ", " << shiftScaleFilter->GetOutput()->GetScalarRange()[1] << "]" << std::endl; return EXIT_SUCCESS; } void CreateImage(vtkImageData* const image) { // Specify the size of the image data image->SetDimensions(2,3,1); #if VTK_MAJOR_VERSION <= 5 image->SetNumberOfScalarComponents(1); image->SetScalarTypeToDouble(); image->AllocateScalars(); #else image->AllocateScalars(VTK_DOUBLE,1); #endif int* dims = image->GetDimensions(); std::cout << "Dims: " << " x: " << dims[0] << " y: " << dims[1] << " z: " << dims[2] << std::endl; for (int z = 0; z < dims[2]; z++) { for (int y = 0; y < dims[1]; y++) { for (int x = 0; x < dims[0]; x++) { double* pixel = static_cast<double*>(image->GetScalarPointer(x,y,z)); pixel[0] =vtkMath::Random(0.0,2000.0); } } } }
CMakeLists.txt¶
cmake_minimum_required(VERSION 2.8) PROJECT(RescaleAnImage) find_package(VTK REQUIRED) include(${VTK_USE_FILE}) add_executable(RescaleAnImage MACOSX_BUNDLE RescaleAnImage.cxx) target_link_libraries(RescaleAnImage ${VTK_LIBRARIES})
Download and Build RescaleAnImage¶
Danger
The generation of tar files has not been ported to the new VTKExamples. Some tarballs may be missing or out-of-date.
Click here to download RescaleAnImage and its CMakeLists.txt file. Once the tarball RescaleAnImage.tar has been downloaded and extracted,
cd RescaleAnImage/build
If VTK is installed:
cmake ..
If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:
cmake -DVTK_DIR:PATH=/home/me/vtk_build ..
Build the project:
make
and run it:
./RescaleAnImage
WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.