A non-contact motion information demodulation method based on arc-string approximation principle

Abstract

The invention discloses a non-contact motion information demodulation method based on the arc-chord approximation principle, comprising: obtaining a digital quadrature baseband signal through sampling; The I-way sampling value and Q-way sampling value of the sampling point are two-dimensional coordinates, and a straight line is fitted by the principal component analysis method, so that the norm sum of the vertical distance between each sampling point and the straight line is the smallest; the direction vector is obtained. , and construct a set of chord vectors based on the I-way sampling value and Q-way sampling value of each two adjacent sampling points; use each chord vector and the direction vector to do the inner product to obtain the inner product result; according to the two adjacent sampling points The approximation of the arc and the chord between the dimensional coordinates, using the positive and negative of the inner product result to superimpose the chord length of each of the chord vectors to obtain the arc length superposition result, and restore the target motion information based on the arc length superposition result . The present invention can improve the robustness, real-time performance and efficiency of motion information demodulation.

Description

technical field [0001] The invention belongs to the field of motion detection, in particular to a non-contact motion information demodulation method based on the arc-string approximation principle. Background technique [0002] In fields such as biomedicine, non-contact motion detection can measure the motion information of dynamic targets, such as human heartbeat and pulse. The specific detection process includes transmitting an electromagnetic wave signal to the detection target; receiving the signal returned from the detection target, down-converting and sampling the signal to obtain a quadrature baseband signal, and then performing phase demodulation on the quadrature baseband signal to recover the target's signal. sports information. Among them, the phase demodulation of the baseband signal is the key to whether the motion information can be accurately recovered. [0003] At present, the most accurate scheme for recovering motion information is the phase demodulation ...

AI Technical Summary

Problems solved by technology

[0018] However, when measuring the life signal of a dynamic human body, the movement of the human body will change the irradiation range of the radar beam, and the DC offset generated by the static target clutter will also change with time, which seriously affects the phase demodulation process of the above scheme, resulting in the demodulation Error, unable to restore target's motion information

Moreover, the process of finding the DC offset in the existing scheme involves the iteration of complex algorithms, which consumes a lot of computing resources, thus affecting the real-time and efficiency of the target's motion detection

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