Resample image python code.

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Hi, i am new to the itk package. Would you have time to do a sample code on Resampling image in python?
i got the c++ version here : https://itk.org/Wiki/ITK/Examples/ImageProcessing/ResampleImageFilter

My need is to reshape the image and plot a histogram between two reshaped images.

Thanks in advance.

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Welcome to ITK, @SantaHub!

Here are a few resampling examples in Python:

https://itk.org/ITKExamples/src/Filtering/ImageGrid/ResampleAScalarImage/Documentation.html

https://itk.org/ITKExamples/src/Filtering/ImageGrid/ResampleAVectorImage/Documentation.html

See the Quick Start Guide on how convert the image pixel buffer to a numpy array. A histogram can be visualized from the array with matplotlib.

However, I would not expect a large difference in the histogram unless there is extreme deformation in the transform.

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Thanks @ma

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How would you do this for a vector image?

I think this would use something like the following:

Dimension = 2
PixelType = itk.RGBPixel[itk.UC]
ImageType = itk.Image[PixelType, Dimension]

the problem I think is that I want to do this in simpleITK, because otherwise I am mixing things together in a convoluted way, and having tried the above I get a type error.

either I need an equivalent SimpleITK version for RGB, or a way to convert a composite sitk transform to itk transform…

I have discovered this :

# Extract first three channels of joined image (assuming RGB)
select = sitk.VectorIndexSelectionCastImageFilter()
channel1_image = select.Execute(joined_image, 0, sitk.sitkUInt8)
channel2_image = select.Execute(joined_image, 1, sitk.sitkUInt8)
channel3_image = select.Execute(joined_image, 2, sitk.sitkUInt8)

I found that I can resample each component individually.

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You should open a new questions, but SimpleITK’s Resample working with RGB or vector pixel types by default, so there is not need to run in on a per component basis.

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@blowekamp Apologies for not making a new question, I will do that.