Objective Based on photoplethysmography can be used to noninvasively the physiological parameters of human such as oxygen saturation and so on.Because of the disturbance of random noise and breathing of human body in the process of signal acquisition, there is high-frequency noise and breathing baseline, which affects the final prediction accuracy of the physiological parameters of human, the resolution of wavelet transform can make the signal and noise shows different characteristics.Therefore wavelet analysis is employed, and then this can remove high-frequency noise and breathing baseline from pulse wave signal.Methods Based on the energy of wavelet details and the maximum decomposition of a period signal and the entire signal, we first confirm the details which represent high- frequency noise and breathing baseline.Then the high frequency noise and baseline of pulse wave signals in the human physiological parameter detection are eliminated.A self-developed measurement device is used to obtain the pulse wave signal and wavelet transform is adopted to decrease high-frequency noise and breathing baseline at the same time.And AC-DC modulation employs ratio to evaluate the effect.Results After the management of wavelet transform, the amplitude of high frequency declines and the stability of AC-DC modulation ratio enhances.Conclusions Wavelet transform can effectively and synchronously remove high-frequency noise and breathing baseline from pulse wave signal, which is beneficial for the improvement of the detection accuracy in the physiological parameters of human body.
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