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To realize continuous blood pressure (BP) measurement, we think the vibrational signal of pulsation waveform has good potential for BP model improvement. In this paper, we used a structured light projection method and a fringe analysis method to develop a non-contact measuring tool which used vibrational waveforms of arterial pulsation signals. Our method, based on a triangular configuration, used a digital light processing (DLP) projector and a camera with frame rate of 46 fps. The fringe pattern with pre-defined spatial carrier frequency was projected on the subject’s wrist. In our configuration design, instantaneous pulsation-induced skin vibrations of subtle amplitude can be observed and recorded within each frame of the fringe pattern. Using a two-dimensional Fourier transform, we chose a frequency region of interest (ROI) filter to collect the spectrum magnitude embedded with the deformation data to deliver the phase retrieval. The phase map was unwrapped using a non-iterative unweighted algorithm based on Fast Fourier Transform (FFT), we obtained the unwrapped phase map. After using a phase-to-height conversion, the results of the full-field dynamic vibrational field were analyzed. Several indicators such as heart rhythm (HR), heart rate variable (HRV), and root mean squared errors (RMSE) were adopted to compare the pulsation signal with the ECG and PPG signals. Our results demonstrated that the peak-to-peak arterial of a pulsation waveform amplitude was about 50-70μm which confirmed the suitability of structured light projection method for continuous pulsation signal monitoring.
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