segmentations_merge
=====================================================

.. py:function:: petpal.preproc.segmentation_tools.segmentations_merge(segmentation_primary: numpy.ndarray, segmentation_secondary: numpy.ndarray, regions: list) -> numpy.ndarray

   Merge segmentations by assigning regions to a primary segmentation image from a secondary
   segmentation. Region indices are pulled from the secondary into the primary from a list.

   Primary and secondary segmentations must have the same shape and orientation.

   :param segmentation_primary: The main segmentation to which new
                                regions will be added.
   :type segmentation_primary: np.ndarray
   :param segmentation_secondary: Distinct segmentation with regions
                                  to add to the primary.
   :type segmentation_secondary: np.ndarray
   :param regions: List of regions to pull from the secondary to add to
                   the primary.
   :type regions: list

   :returns: *segmentation_primary (np.ndarray)* --

             The input segmentation with new
                 regions added.