Method for identifying human joint micro-motion by using depth camera to assist radar

Abstract

The invention discloses a method for recognizing human body joint micro-motion by using a depth camera to assist a radar, and the method comprises the steps: receiving the data collected by the radar and the depth camera for the motion states of a plurality of human body targets at the same time, and obtaining the radar data and the depth camera data of the micro-motion of the human body targets; processing according to a radar system to obtain radar data of a one-dimensional time sequence; performing time-frequency analysis on the processed radar data to obtain micro-Doppler features corresponding to the human body target; performing low-pass filtering processing on the depth camera data, and converting the filtered distance information of each joint of a certain human body target along with the time into the speed information of each joint along with the time; and matching the micro-Doppler feature of a certain human body target with the speed information of each joint changing along with time. According to the method, the problem that micro-Doppler frequency components corresponding to different joints of a human body target in radar micro-Doppler features are difficult to distinguish is solved.

Description

technical field [0001] The invention relates to the application field of human body micro-Doppler characteristics and depth camera data, in particular to a method for using a depth camera to assist radar to identify micro-motion of human joints. Background technique [0002] When the radar target moves radially relative to the radar, the frequency of the radar echo will produce the Doppler effect. In many cases, in addition to the translational motion of an object, any structural component of the object will also have some oscillatory motion - is called the micro-motion of the object. An example is the rotating helical blades of a helicopter. The flapping wings of birds during flight and the swinging arms and legs of pedestrians can all be called micro-motions. Micro-motion can cause Doppler frequency modulation in the transmitted radar signal near the carrier frequency, and this Doppler frequency modulation is called micro-Doppler frequency. The micro-motion characterist...

AI Technical Summary

Problems solved by technology

However, for the micro-motion of each joint of the human target, the single-channel radar can only obtain the micro-Doppler characteristics of one (or more) human targets as a whole, and in the case of no prior knowledge or complex motion state, only through the radar It is difficult to distinguish the contribution of each joint of the human body in the micro-Doppler feature

Therefore, the micro-Doppler features obtained only by single-channel radar cannot be quantitatively analyzed for the micro-Doppler frequency contributed by each joint of the human target

See reference [1] (J.Li and P.Stoica, MIMORadar Signal Processing, John Wiley&Sons, 2008.) A solution is proposed to increase the number of channels of the radar system and use multiple-input multiple-output technology, but this will seriously increase The complexity of the radar system, considering that a radar system with high system complexity is undesirable in civilian equipment, it is not recommended to use multiple-input multiple-output technology to separate the micro-Doppler frequencies of each joint or limb

Another solution is to use an algorithm to estimate the micro-Doppler frequency of different limbs, see reference [2] (R.G.Raj, V.C.Chen, and R.Lipps, "Analysis of radar human gait signatures," IET Image Process,Vol.4,No.3,2010.), but the algorithm proposed above has only been verified in the simple motion state in the simulated micro-Doppler feature

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