1. Filter out high-frequency noise

2. Find significant startle regions

   A startle region is first roughly defined as a "large" region where
   the first sample point has the only "significant" positive first
   difference, and no other point in the region has such a "significant"
   positive first difference.

  "large" region means >31 sample points by default
  "significant" first difference means >0.003 by default

2. Fine Tuning

   Given the startle regions, we define the beginning of a startle
   (beg) to be the first sample point before a region with a negative
   first difference and the end of the startle (end) to be the maximum
   point between the beginning of this region and the beginning of the
   next. 

   The duration of the startle is then end-beg and the magnitude of the
   startle is s(end)-s(beg), where s is the signal.