Abstract:

The weak vital periodic signals(respiration and heartbeat) are easy to be submerged by high level noises as human body is unmovable, whose frequencies are difficult to be detected. In order to solve this problem, a new method based on the combination of autocorrelation and chaotic oscillator phase transformation theory is proposed to detect the weak vital periodic signals. The proposed method makes use of the conventional autocorrelation in the time domain to filter noises primarily, and then employs the improved chaotic oscillator array to distill the usable signals, which takes advantage of autocorrelation and chaotic detection in the filed of noiserestraining and signaldetecting respectively. The simulation analysis indicates that the proposed method succeeds in detecting two weak vital periodic signals in the context of high level noises, and furthermore the signaltonoise ratio threshold of the proposed method achieves 81.43dB, which is lower than either autocorrelation or chaotic oscillator.

Key words: weak signal;autocorrelation;chaotic detection;random noise;signaltonoise ratio