How to resize a 3D image

Algorithms
1

Hi, I’m trying to resize a 3D image to an specific size, but I’m getting as a result a white image with some black slices.

Here is the code:

sitk::Image imResize3(sitk::Image input, sitk::Image output_size_image)
{
    std::vector<unsigned int> new_dims = output_size_image.GetSize();
    std::vector<unsigned int> old_dims = input.GetSize();

    sitk::AffineTransform affine = sitk::AffineTransform(3);
    std::vector<double> affine_matrix = affine.GetMatrix();
    affine_matrix[0] = new_dims[0]/old_dims[0];
    affine_matrix[4] = new_dims[1]/old_dims[1];
    affine_matrix[8] = new_dims[2]/old_dims[2];

    affine.SetMatrix(affine_matrix);
    sitk::Image resampled_image = sitk::Resample(input, output_size_image, affine, sitk::sitkBSplineResamplerOrder3);
    return resampled_image;
}

The function receives the input image, which the user wants to resize, and the output image, which has the target size. The input image has the size: 256x256x26 and the output image has 182x218x182. Both images have spacing of 1.

Here is the input image.

image
image.png957×953 109 KB

Here is the output image.

image
image.png958×953 21.3 KB

So, how can I solve this problem?

Thank you.

2

You should not modify the scale of the transform, you want identity transform. What you need to modify is the size and spacing of the output_size_image. Also take a look at a previous discussion:

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