vtkImageDifference fail to find obvious difference
The following two images are seen as 0 difference by vtkImageDifference::GetThresholdedError. This is unexpected
#include <vtkImageDifference.h>
#include <vtkNew.h>
#include <vtkPNGReader.h>
#include <iostream>
int main(int argc, char* argv[])
{
vtkNew<vtkPNGReader> reader1;
reader1->SetFileName(argv[1]);
reader1->Update();
vtkNew<vtkPNGReader> reader2;
reader2->SetFileName(argv[2]);
reader2->Update();
vtkNew<vtkImageDifference> differenceFilter;
// differenceFilter->SetThreshold(0);
differenceFilter->SetInputConnection(reader1->GetOutputPort());
differenceFilter->SetImageConnection(reader2->GetOutputPort());
differenceFilter->Update();
std::cout<<differenceFilter->GetThresholdedError()<<std::endl;
return EXIT_SUCCESS;
}