envelope {biosignalEMG} | R Documentation |
Computes the RMS-envelope, the MA-envelope ot the LE-envelope of an EMG signal.
envelope(data, channel, method = c("MA","RMS","LE"), wsize, cutoff, n = 2, data.name, ...)
data |
an ‘emg’ object. |
channel |
in case of multi-channel data, |
method |
a string, "MA" (default) for MA-envelope, "RMS" for the RMS-envelope and "LE" for the LE-envelope. |
wsize |
determines the length of the moving window that is used to calculate the local averages of the data in RMS and MA envelopes. |
cutoff |
cutoff frequency in Hertz for the lowpass filter used in LE-envelope. |
n |
filter order for the lowpass filter used in LE-envelope. |
data.name |
a string specifying the name of the variable which will appears on the plots. If empty or not provided is taken from the object given as |
... |
Optional parameters for a MA-envelope: |
The MA-envelope corresponds to the moving average of the rectified EMG.
The RMS-envelope corresponds to the moving average of
y_i=(x_i-\mu_{x})^2
where x_i
is each value of the EMG signal and \mu_{x}
is the overall mean of the EMG signal.
LE-envelope or linear envelope is lowpass filtered rectified signal.
An ‘emg’ object containing the envelope of the EMG.
J.A. Guerrero jaguerrero@correo.uaa.mx
Konrad P. (2005) The ABC of EMG: A Practical Introduction to Kinesiological Electromyography. Version 1.0, Noraxon INC. USA.
# Simulate 5 seconds of an EMG
emgx <- syntheticemg(n.length.out = 5000, on.sd = 1, on.duration.mean = 350,
on.duration.sd = 10, off.sd = 0.05, off.duration.mean = 300, off.duration.sd = 20,
on.mode.pos = 0.75, shape.factor = 0.5, samplingrate = 1000, units = "mV",
data.name = "Synthetic EMG")
# MA-envelope
emgma <- envelope(emgx, method = "MA", wsize = 60)
# Superimpose the envelope on the EMG
plot(emgx, main = "MA-envelope")
plot(emgma, add = TRUE, lwd = 4, col = "red")
# RMS-envelope
emgrms <- envelope(emgx, method = "RMS", wsize = 60)
# Superimpose the envelope on the EMG
plot(emgx, main = "RMS-envelope")
plot(emgrms, add = TRUE, lwd = 4, col = "red")
# RMS-envelope
emgle <- envelope(emgx, method = "LE", cutoff = 10) #10Hz
# Superimpose the envelope on the EMG
plot(emgx, main = "LE-envelope")
plot(emgle, add = TRUE, lwd = 4, col = "red")