t matrix at the shortest length scale (``cwt[0, loc]``), the
    noise is the `noise_perc`\ th percentile of datapoints contained within a
    window of `window_size` around ``cwt[0, loc]``.
noise_perc : float, optional
    When calculating the noise floor, percentile of data points
    examined below which to consider noise. Calculated using
    scipy.stats.scoreatpercentile.

References
----------
.. [1] Bioinformatics (2006) 22 (17): 2059-2065.
   :doi:`10.1093/bioinformatics/btl355`

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