[Non-linear compression for noises in non-contact vital signs detecting system]

A method for compressing the noises overlapping in the breath and heart signals of human beings, detected by the non-contact vital signs detecting system during the display of the waveforms in time domain, is discussed in this paper in detail. And what's more, the problem that the noise level is changed along with the increase of the gain of AD data-acquisition card and the display--gain of the software is solved by researching into the threshold of noise-level contraction in two types of circumstance in the lab, and the result of the breath and heart signal in the condition of lower noise is realized as well.