class_docstr: number of zero crossings among two consecutive samples above a certain threshold for each
  variable in the segmented time series
class_docstr_tok: ["number","of","zero","crossings","among","two","consecutive","samples","above","a","certain","threshold","for","each","variable","in","the","segmented","time","series"]
code: def __init__(self, threshold=0):
      self.threshold = threshold
  
imports: import numpy
  from scipy import stats
label_desc: Use image node_id 1 to create a new zero_crossing object from inherited base classes: object with example: obj = zero_crossing(threshold)