[Insight-users] parameter tuning for image registration.

[Xi Liang]

Dear all,

Parameter tuning in the image registration is really a tough job for me, due
to lack of analysis skills. Everytime when I have a new application, I have
to spend a huge amount of time to find the right parameter set. Or maybe I
was "guessing" the parameters. I understand there are so many different
algorithms in image registration, and in each algorithm, again so many
different choice for each component, e.g. optimizer, sampler, and metrics.
In each component, there are several parameters to tune.

Is there any reference that help parameters tuning in image processing? Any
introduction on how to analyse the result by changing parameters, not only
 from high level, e.g. improve the metric value. It is more like, if I want
to tune the parameters in an optimizer, I might want to analyse the
gradients, or might draw some graph on the step size, or convergence.

I understand the parameter tuning in this way, as a starter of image
processing. All comments are highly appreciated. There is no uniform good
and robust parameter set for a registration algorithm. If you want to choose
the right parameters, you have to understand each component in a
registration algorithm how they work, and can be able to mathematically
analysis on results in each components. However, this seems a bit
unrealistic.

 Another quick way is start from the code and parameters available, and
gradually understand the algorithm, which is what I am doing. However, at
this stage, I still cannot do a systematically analyse on each component in
a Bspline based registration result by using different parameters. I just
try different combination to get the highest value of SSD, or MI, or those
metric value, or just though visual check. I would like to analyse the
behavior of each component in a lower level, but only look at the final
registration result.

Or maybe I should not ask how to do parameter tuning, I should ask how to do
image analysis. However, most of the book just discuss on the algorithm, and
do not discuss how to analyse or "debug" the wrong component.

This question might be a little bit confusing, and I just try to analyse and
figure out what is the true problem while typing.

Kind regards,

Xi
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