Final part of the PPG not delineated

[levsilva]

Hi,

I am testing the delineation of PPGs and noticed that the final part of the signal is not delineated. When I use 20 seconds of data, the final 10 seconds are not delineated:

However, if I use 40 seconds of the same signal (same starting point with an additional 20 seconds), the delineation happens in all but the final 3 seconds:

Below is the code that I am using to generate the plots. Would you know why does this happen?

Thank you in advance!
Luiz

# `ppg_wave` in the PPG waveform loaded previously

signal = DotMap()
signal.start_sig = 0  # the first sample of the signal to be analyzed
signal.end_sig = len(ppg_wave)  # the last sample of the signal to be analyzed
signal.ppg = ppg_wave
signal.fs = fs
signal.name = ppg_name

# Calculate the first, second, and third derivatives of the PPG signal
# pyPPG does the same, except for additional smoothing if fs >= 150
signal.ppg = ppg_wave
signal.vpg = np.gradient(ppg_wave)
signal.apg = np.gradient(signal.vpg)
signal.jpg = np.gradient(signal.apg)

# Correction for fiducial points
corr_on = ['on', 'dn', 'dp', 'v', 'w', 'f']
correction = pd.DataFrame()
correction.loc[0, corr_on] = True
signal.correction = correction

ppg_obj = PPG(signal, check_ppg_len=False)  # Create a PPG class

fpex = fiducials.FpCollection(ppg_obj)  # Initialize the fiducials package
fiducial_points = fpex.get_fiducials(ppg_obj)  # Get fiducial points      
fiducial_obj = Fiducials(fiducial_points)  # Create a fiducials class

# Plot fiducial points
from pyPPG.datahandling import plot_fiducials
plot_fiducials(ppg_obj, fiducial_obj, savefig=False, legend_fontsize=8)

[HichDh]

+1 also experiencing the same issue. Although my signals are 20s long and only the last part is not delineated. Did you figure out how to fix it?

[godamartonaron]

The dicrotic notch detection algorithm requires a minimum 15-second window. Therefore, you must use at least this duration, with the last 10 seconds remaining undetected. For shorter fiducial point detection, you can see the validation module, where a 2-second PPG signal was used.
https://github.com/godamartonaron/GODA_pyPPG/tree/main/pyPPG/validation