Contact-free detection of respiration signal from continuously moving-object noise via a Doppler radar using adaptive line enhancer

Doppler radar has been used to search survivors buried under earthquake rubble by contact-free detection of respiration signals. However, the respiration signals were minute and easy to be polluted by noise from moving-object around the survivor such as swing of flowers, leaves and bushes. In order to restrain the noise and improve the signal-to-noise ratio (SNR), the Adaptive Line Enhancer (ALE) was used to detect the respiration signals. Simulation and experiment results showed that the SNR was significantly improved.