How to get metric value for a given set of transform parameters in ITK V4?

Algorithms
1

I’m trying to plot a profile of cost function (or metric) values for a 3D image registration study. This can be done easily in ITK V3 with the itk::ImageToImageMetric::GetValue(const ParametersType &parameters) function. So I can change the parameters in the argument to probe the cost function in the parametric space. However in ITK V4, only the function itk::ImageToImageMetricv4::GetValue() exists with no argument taken. I’m wondering how to get it done in the new registration frame. Any hints or examples? I’ll appreciate it very much if anyone could help!

2

ImageToImageMetricv4 inherits SetParameters(). You should call that prior to calling GetValue().

1 Like
3

Thank you very much, I found the answer by myself before reading your message.

Though, there is a problem in my code. My loop stops when the following error is raise :

RuntimeError: /work/ITK-source/ITK/Modules/Registration/Common/include/itkMeanSquaresImageToImageMetric.hxx:126:
ITK ERROR: MeanSquaresImageToImageMetric(0x5631eee2a330): Too many samples map outside moving image buffer: 0 / 2215440

How can I keep running for other values after one of the tuple (x,y) failed?

4

Use try/catch syntax to avoid that. Pseudocode:

for x ...
  for y ...
    try
    {
    metricXY = evaluate(fixedImage, movingImage, x, y);
    metrics[y][x] = metricXY;
    }
    catch(const itk::Exception& exc)
    {
    std::cout<<... // or just ignore it
    }