rescale_image#

petpal.preproc.image_operations_4d.rescale_image(input_image: ants.core.ANTsImage, rescale_constant: float, op: str = '/') → ants.core.ANTsImage#

Rescales a 3D or 4D ANTsImage intensity values by performing division or multiplication with a given constant.

This function supports two operations: dividing the input image by a rescale constant or multiplying it by the constant. Division is only allowed with a positive rescale constant to avoid invalid operations. The operation is applied element-wise across the image data.

Parameters:

  • input_image (ants.core.ANTsImage) – Input image, given as an ANTsImage object.

  • rescale_constant (float) – The constant to rescale the image intensities. For division (op=”/”), this value must be greater than zero.

  • op (str, optional) – Operation to perform, either ‘/’ for division or ‘*’ for multiplication. Default is ‘/’.

Returns:

ants.core.ANTsImage – The rescaled ANTsImage with updated intensity values.

Raises:

  • AssertionError – If op is not one of ‘/’ or ‘*’.

  • AssertionError – If division (op=”/”) is requested, but rescale_constant is not greater than zero.

Example

import ants
from petpal.preproc.image_operations_4d import rescale_image

# Load a sample ANTsImage
input_img = ants.image_read('example_image.nii')

# Rescale intensities by division with a constant (e.g., 2.0)
rescaled_img = rescale_image(input_image=input_img, rescale_constant=2.0, op='/')

# Rescale intensities by multiplication with a constant (e.g., 1.5)
rescaled_img = rescale_image(input_image=input_img, rescale_constant=1.5, op='*')
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