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Comparison of the parameters of PPG waveforms measured in the hot spots found in a palm of different subjects with and without polarization filtration. a) Relative difference in the amplitude of blood pulsations at the heartbeat frequency. b) Ratio of the root-mean-square of the high-frequency noise measured without polarization filtration to that with polarization filtration. The red dashed line in the graph (a) indicates the mean BPA difference.
