FindStartParams: FindStartParams

In stw32/PulseWaveform: Extraction of Photoplethysmography Waveform Features and Decomposition Modeling of Pulse Waveforms

FindStartParams

Description

FindStartParams generates starting parameters for the HED model, using estimates derived from the data itself. Since the HED model assumes both decay and excess elements, an approximation of the decay is removed from the original waveform data to infer the excess. Once the excess is defined, peaks in the excess are searched for within empirically defined ranges. Values for width, timing and amplitude for each peak can then be inferred.

Usage

FindStartParams(batch_number, beats_in, beat, ppg, gs = model2.GetSegment, e = model2.Excess, sep = model2.SubtractExcessPeak, o_points = inflexX[o_orig], wuv = wuv, inflexX = inflexX, all_beats = FALSE, plot = FALSE)

Arguments

batch_number	the number of batches of waves to process
beats_in	the number of beats in a batch, over which the width, reflectance timing, and decay rate parameters will be fixed
beat	empty dataframe to be filled with starting parameters
ppg	ppg time series (unsegmented)
gs	model2.GetSegment function
e	model2.Excess function
sep	model2.SubtractExcessPeak function
o_points	vector of locations of the o (origin) points for each waveform in the ppg time series
wuv	dataframe of locations of the w, u and v points for each waveform in the ppg time series
inflexX	vector of x coordinates for each inflection point on the ppg time series
all_beats	logical, if true ensures all available beats in the time series are modeled
plot	logical, if true plots each beat for which parameters are being estimated

Value

temp	list consisting of the following:
beat	updated dataframe populated with estimated starting parameters, to be used as input for downhill simplex
ppg	additional columns providing parallel time series of inferred baseline, excess and residuals of ppg data

Examples

temp <- FindStartParams(batch_number, beats_in, beat, ppg, gs = model2.GetSegment,
                                  e = model2.Excess, sep = model2.SubtractExcessPeak,
                                  o_points = inflexX[o_orig], wuv = wuv, inflexX = inflexX, all_beats)

stw32/PulseWaveform documentation built on Dec. 6, 2022, 2:50 a.m.