Change optimizer parameters for multiresolution image registration

Algorithms
1

Hi all,

I saw the example of MultiResImageRegistration1.cxx can change the optimizer parameters (e.g learning rate) for different level of a image pyramid. But when I learnt from it to write python-supported ITK code, the optimizer parameters did not change. Did I miss something in the code below? Thanks in advance.

Here is my code

rigid_registration = itk.ImageRegistrationMethodv4[itk.Image.F3, itk.Image.F3].New()

rigid_optimizer = itk.RegularStepGradientDescentOptimizerv4[itk.D].New()
rigid_optimizer.SetScales(rigid_optimizer_scales)
rigid_optimizer.ReturnBestParametersAndValueOn()

if rigid_registration.GetCurrentLevel() == 0:
rigid_optimizer.SetLearningRate(16.0)
rigid_optimizer.SetMinimumStepLength(2.5)
else:
rigid_optimizer.SetLearningRate(rigid_optimizer.GetCurrentStepLength())
rigid_optimizer.SetMinimumStepLength(rigid_optimizer.GetMinimumStepLength()*0.2)

registration

rigid_registration.SetFixedImage(caster_fixed_image.GetOutput())
rigid_registration.SetMovingImage(caster_moving_image.GetOutput())
rigid_registration.SetMetric(rigid_metric)
rigid_registration.SetOptimizer(rigid_optimizer)
rigid_registration.SetInitialTransform(rigid_transform)

def iterationUpdate():
print(rigid_optimizer.GetLearningRate())

iteration_command = itk.PyCommand.New()
iteration_command.SetCommandCallable(iterationUpdate)
rigid_optimizer.AddObserver(itk.IterationEvent(), iteration_command)

rigid_registration.Update()

2

Hi @zhuangming.shen,

Could the complete code and data please be shared so the issue can be reproduced?

Thanks,
Matt

3

Hi Matt,

Thanks for your reply. But the Upload in discourse can only support file formats such as jpg, jpeg, png, etc. How can I shared my code and data?

Regards,

Zhuangming Shen

4

Hi Matt,

I just sent my code and data to your kitware’s email.

Regards,

Zhuangming Shen

5

Hi Zhuangming Shen,

Thank you for sending the data. I also fixed the Discourse setting so we can upload any file type now.

However, the file was still over the size limit, so I uploaded it here:

https://drive.google.com/file/d/0B986LSX8iqF-ckxkS1UyemJVYWVyVlc3Y0RWQ1ljdGdiWmxV/view?usp=sharing

Thanks,
Matt

1 Like
6

Great! The limitation to just embedding images was so annoying! The only option was to make code part of the post.