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from scipy import signal
import numpy as np
from .base import VHRMethod
class CHROM(VHRMethod):
""" This method is described in the following paper:
"Remote heart rate variability for emotional state monitoring"
by Y. Benezeth, P. Li, R. Macwan, K. Nakamura, R. Gomez, F. Yang
"""
methodName = 'CHROM'
def __init__(self, **kwargs):
super(CHROM, self).__init__(**kwargs)
def apply(self, X):
#self.RGB = self.getMeanRGB()
#X = signal.detrend(self.RGB.T)
# calculation of new X and Y
Xcomp = 3*X[0] - 2*X[1]
Ycomp = (1.5*X[0])+X[1]-(1.5*X[2])
# standard deviations
sX = np.std(Xcomp)
sY = np.std(Ycomp)
alpha = sX/sY
# -- rPPG signal
bvp = Xcomp-alpha*Ycomp
return bvp |