# -*- coding: utf-8 -*-
"""
biosppy.signals.bvp
-------------------
This module provides methods to process Blood Volume Pulse (BVP) signals.
-------- DEPRECATED --------
PLEASE, USE THE PPG MODULE
This module was left for compatibility
----------------------------
:copyright: (c) 2015-2018 by Instituto de Telecomunicacoes
:license: BSD 3-clause, see LICENSE for more details.
"""
# Imports
# compat
from __future__ import absolute_import, division, print_function
from six.moves import range
# 3rd party
import numpy as np
# local
from . import tools as st
from . import ppg
from .. import plotting, utils
[docs]def bvp(signal=None, sampling_rate=1000., path=None, show=True):
"""Process a raw BVP signal and extract relevant signal features using
default parameters.
Parameters
----------
signal : array
Raw BVP signal.
sampling_rate : int, float, optional
Sampling frequency (Hz).
path : str, optional
If provided, the plot will be saved to the specified file.
show : bool, optional
If True, show a summary plot.
Returns
-------
ts : array
Signal time axis reference (seconds).
filtered : array
Filtered BVP signal.
onsets : array
Indices of BVP pulse onsets.
heart_rate_ts : array
Heart rate time axis reference (seconds).
heart_rate : array
Instantaneous heart rate (bpm).
"""
# check inputs
if signal is None:
raise TypeError("Please specify an input signal.")
# ensure numpy
signal = np.array(signal)
sampling_rate = float(sampling_rate)
# filter signal
filtered, _, _ = st.filter_signal(signal=signal,
ftype='butter',
band='bandpass',
order=4,
frequency=[1, 8],
sampling_rate=sampling_rate)
# find onsets
onsets,_ = ppg.find_onsets_elgendi2013(signal=filtered, sampling_rate=sampling_rate)
# compute heart rate
hr_idx, hr = st.get_heart_rate(beats=onsets,
sampling_rate=sampling_rate,
smooth=True,
size=3)
# get time vectors
length = len(signal)
T = (length - 1) / sampling_rate
ts = np.linspace(0, T, length, endpoint=False)
ts_hr = ts[hr_idx]
# plot
if show:
plotting.plot_bvp(ts=ts,
raw=signal,
filtered=filtered,
onsets=onsets,
heart_rate_ts=ts_hr,
heart_rate=hr,
path=path,
show=True)
# output
args = (ts, filtered, onsets, ts_hr, hr)
names = ('ts', 'filtered', 'onsets', 'heart_rate_ts', 'heart_rate')
return utils.ReturnTuple(args, names)