code: def _extract_intensities(image, mask=slice(None)):
      """
      Internal, single-image version of `intensities`.
      """
      return numpy.array(image, copy=True)[mask].ravel()
  
imports: import numpy
  from scipy.ndimage import gaussian_filter, median_filter
  from scipy.ndimage import gaussian_gradient_magnitude
  from scipy.interpolate.interpolate import interp1d
  from scipy.ndimage import distance_transform_edt
  from scipy.ndimage._ni_support import _get_output
  from .utilities import join
  from ..core import ArgumentError
  from ..filter import sum_filter
label_desc: Use image node_id 20 for calling a global function with example usage: _extract_intensities(image, mask) and returns: numpy