The invention discloses a non-contact
respiration detection method. First, an access point (AP), a
base station (STA) and a capture device are arranged in a target area, and
channel state information is obtained by capturing a
beamforming feedback frame (BFI) periodically sent from the STA to the AP. And then, decompressing and extracting amplitude signals and
time information in the BFI frame, performing phase-space reconstruction on the extracted representative
subcarrier signals of the antenna combination, and extracting and evaluating the optimal antenna combination through dynamic characteristics. Thirdly, performing Hampel filtering on the
subcarrier amplitude signals of the optimal antenna combination to remove abnormal values, performing phase-space reconstruction and
dynamic feature extraction on all subcarriers, and selecting the optimal
subcarrier by using a K-means clustering
algorithm; and then, Savitzky-Golay filtering and band-pass filtering are carried out on the selected optimal subcarrier
signal, and linear interpolation is carried out through
principal component analysis (PCA) dimension reduction to obtain an equally-spaced sampling
signal. And finally, performing
fast Fourier transform (FFT) on the processed
signal, and estimating the
respiratory rate through an innovative
peak detection algorithm. The invention provides a non-contact
respiration detection method by utilizing a
phase space reconstruction and
dynamic feature extraction technology, and compared with a traditional method, the method can better capture nonlinear dynamic features of signals and more comprehensively evaluate dynamic features of each subcarrier, so that the subcarrier most suitable for
respiration detection is selected, and the detection accuracy is improved. The
breathing signal and the interference signal are effectively distinguished, and the accuracy and robustness of non-contact
breathing detection based on the Wi-Fi signal are remarkably improved.