The Technology Of Real-time Detecting And Processing Active Electromagnetic Life Signal

The technology of real-time detecting and processing active electromagnetic life signal is mainly based on the principle of Doppler frequency shifting. When the Electromagnetic wave was reflected by the body, we can extract life relevant characteristics information from the echo after properly being processed. Since signal was modulated by human life activities, such as breathing, heartbeating, etc, some parameters of the signal were changed. From the echo signal, we can estimate whether life is alive, active and the number of lives. The tradional life-detection equipments are always limited due to the external complicated environment, however,the method of real-time detecting and processing active electromagnetic life signal have the better anti-interference capability. This method is worth greater application, It not only can rescue injured persons quickly after earthquakes, collapse, mountain avalanche, and other disasters, but also can be used to medical care, prison surveillance as well as anti-terrorism fields and so on.Life signals are low-velocity and slow-change target signals with very small Doppler frequency shifts and so weak that echo signals were easily submerged in the serious clutter and noise. The key in this paper is to detect and extract the weak target signal, and recognize whether life is alive,active and the number of lives availably.This thesis designs a series of methods to recognize life signal from the echo. Firstly, the d4 wavelet which is based on the muti- resolution characteristic of wavelet transform was proposed to detect and extract life signal in the noise background. Secondly, the energy ratio of breathing and movement, parameters estimating of wave resonance and WD(Wigner Distribution)were designed to distinguish life relevant characteristics information automatically. This method has high efficiency and good practicability, and can provide the intuitionistic and credible information for the operator.Based on the designed algorithm framework, the life signal real-time detecting and processing system was designed. The kernel of the hardware part of the system is AD7707 and TMS320C6711B. The system can realize the high-speed transmiting, real-time processing and displaying of the data. It is not only tiny and compact, but also have better anti-interference and detecting ability. Moreover, it can provide the well hardware plat for the stable software running.Based on the TMS320C6711B, the software part of the system is designed under the CCS development software, which contains design and realization of DSP software, as well as code design of Bootloader, system initializing, interrupt service, data communication, FIR filtering, FFT and so on. The software codes of DSP part were designed reasonably, which make the life signal collecting and processing efficiently. It realized system control and data processing, and real-time display of results, as well as time-frequency waveform figures.