class_docstr: This class enables the extraction of image features (Harilick
  features) and basic statistics over a segmentation
class_docstr_tok: ["This","class","enables","the","extraction","of","image","features","(","Harilick","features",")","and","basic","statistics","over","a","segmentation"]
docstr: Calculates the Surface area / Volume ratio in terms of Probabilistic
  Count, Binarised count, Probabilistic Volume, Binarised Volume
  
  :return:
docstr_tok: ["Calculates","the","Surface","area","\/","Volume","ratio","in","terms","of","Probabilistic","Count",",","Binarised","count",",","Probabilistic","Volume",",","Binarised","Volume",":","return",":"]
code: def sav(self):
      """
      Calculates the Surface area / Volume ratio in terms of Probabilistic
      Count, Binarised count, Probabilistic Volume, Binarised Volume
  
      :return:
      """
      Sn, Snb, Sv, Svb = self.surface()
      Vn, Vnb, Vv, Vvb = self.volume()
      return Sn / Vn, Snb / Vnb, Sv / Vv, Svb / Vvb
  
imports: from __future__ import absolute_import, print_function, division
  import numpy
  import numpy.ma
  import math
  import scipy.stats.mstats
  import scipy.ndimage
  from niftynet.utilities.util_common import MorphologyOps, CacheFunctionOutput
label_desc: Use image node_id 35 for calling the RegionProperties obj's underlying member method code with example usage: obj.sav() and returns: unknown,  unknown,  unknown,  unknown