code: def peakdet(v, delta, x=None):
      """
      Converted from MATLAB script at http://billauer.co.il/peakdet.html
  
      Returns two arrays
  
      function [maxtab, mintab]=peakdet(v, delta, x)
      %PEAKDET Detect peaks in a vector
      %        [MAXTAB, MINTAB] = PEAKDET(V, DELTA) finds the local
      %        maxima and minima ("peaks") in the vector V.
      %        MAXTAB and MINTAB consists of two columns. Column 1
      %        contains indices in V, and column 2 the found values.
      %
      %        With [MAXTAB, MINTAB] = PEAKDET(V, DELTA, X) the indices
      %        in MAXTAB and MINTAB are replaced with the corresponding
      %        X-values.
      %
      %        A point is considered a maximum peak if it has the maximal
      %        value, and was preceded (to the left) by a value lower by
      %        DELTA.
  
      % Eli Billauer, 3.4.05
      % This function is released to the public domain; Any use is allowed.
  
      """
      maxtab = []
      mintab = []
  
      if x is None:
          x = numpy.arange(len(v))
  
      v = numpy.asarray(v)
  
      if len(v) != len(x):
          sys.exit("Input vectors v and x must have same length")
  
      if not numpy.isscalar(delta):
          sys.exit("Input argument delta must be a scalar")
  
      if delta <= 0:
          sys.exit("Input argument delta must be positive")
  
      mn, mx = numpy.Inf, -numpy.Inf
      mnpos, mxpos = numpy.NaN, numpy.NaN
  
      lookformax = True
  
      for i in numpy.arange(len(v)):
          this = v[i]
          if this > mx:
              mx = this
              mxpos = x[i]
          if this < mn:
              mn = this
              mnpos = x[i]
  
          if lookformax:
              if this < mx - delta:
                  maxtab.append(mxpos)
                  mn = this
                  mnpos = x[i]
                  lookformax = False
          else:
              if this > mn + delta:
                  mintab.append(mnpos)
                  mx = this
                  mxpos = x[i]
                  lookformax = True
  
      return numpy.array(maxtab), numpy.array(mintab)
  
imports: import sys, os, numpy
label_desc: Use image node_id 4 for calling a global function with example usage: peakdet(v, delta, x) and returns: numpy,  numpy