Padding of 3d images

I have a question regarding the padding of 3d images (.nrrd). Say my image dimension is [256,197,19] and I want my image to have a size of length and width of 256 and channel 30 making it [256,256,30]. What is the syntax for padding of zeros?

If i were to use np.pad(data,((256,----))then how do I adjust my channel width from 19 to 30?

Thank you so much!!!

Medical images are not just specified by a 3D array of voxels but also by the origin, spacing, and axis directions of the image. Therefore, padding is generally not sufficient to bring images into the same space. Instead, images are resampled to have matching array size, origin, spacing, and axis directions.

This is a built-in feature in many modules (e.g., when you export a segmentation then you can specify a reference volume that specifies the desired geometry) and there are also several modules developed specifically for just resampling (see for example how one is used in this example). If you describe what you would like to achieve, then we can give more specific advice.