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
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.