Derivatives & Metric

Today I was looking into ways to improve the registration. One thing that needs to be analyzed is how the derivative is computed in the itk:IntensityProfileMetric. This value could be making the optimizer go off in the wrong direction. I also need to look at the optimizer to see how it takes into account the derivative and how it looks at the value of the metric to decide on what direction to take next. Another thing that needs to be improved is loading all the necessary components of the itk::IntensityProfileMetric. Right now it instantiates an instance of the intensity process class in each iteration, I need to make them class members and do all of that work once. Another improvement would be to find what is making the output of the command iteration class, that tells what the parameters of the registration are, skip so many lines before it enters another value.

The fit to the values of the intensity profile could also need some help, because in some instances it seems as though it is coming off giving an error that is bringing the ellipse closer to the wrong direction. Smoothing has been implemented, but the intensity profile metric class needs to be adjusted to allow for testing since it is too slow.