Multi-person pose recognition system using a zigbee wireless sensor network
First Claim
1. A method for estimating a body pose in a body pose detection module provided with a triaxial accelerometer within a wireless sensor network of a plurality of body pose detection modules arranged to detect and simultaneously monitor body poses of multiple users, the method comprising steps of:
- performing signal pre-processing of a triaxial acceleration signal readout from the triaxial accelerometer at the body pose detection module attached to a user body so as to abstract a dynamic acceleration and a static acceleration of the triaxial acceleration signal;
determining whether the dynamic acceleration of the triaxial acceleration signal is abnormal indicating that a body pose is a falling pose; and
when the dynamic acceleration of the triaxial acceleration signal is not abnormal, analyzing the dynamic acceleration of the triaxial acceleration signal to determine whether a body pose is one of a static pose and a dynamic pose,wherein the signal preprocessing is performed by;
sampling from the triaxial acceleration signal readout from the triaxial accelerometer, each of sensing axes collecting 256 acceleration data, with a sampling frequency of 128 Hz and performing the signal pre-processing once at every two seconds;
subjecting acceleration data of the sensing axes of the triaxial acceleration signal to an eight-layer Haar wavelet transform;
maintaining a wavelet transform coefficient of the eight-layer Haar wavelet transform with a lowest frequency, while omitting other wavelet transform coefficients;
converting the wavelet transform coefficient of the lowest frequency into a time domain to represent the static acceleration of the triaxial acceleration signal; and
subtracting the static acceleration from the triaxial acceleration signal to obtain the dynamic acceleration of the triaxial acceleration signal.
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Abstract
In the present invention, a multi-person pose recognition system has been developed. This system includes a body pose detection module, a CC2420DBK board and a multi-person pose monitoring software module. The body pose detection module includes a triaxial accelerometer, a Zigbee chip and an 8-bit microcontroller. Several body pose detection modules and the CC2420DBK board form a Zigbee wireless sensor network (WSN). The CC2420DBK board functions as the receiver of the Zigbee WSN and communicates with a robot onboard computer or a host computer through a RS-232 port. The multi-person pose monitoring software monitors and records activities of multiple users simultaneously. The present invention provides a pose recognition algorithm by combining time-domain analysis and wavelet transform analysis. This algorithm has been implemented in the microcontroller of a body pose estimation module. Through the algorithm, the system can recognize seven body poses: falling, standing, sitting, lying, walking, going upstairs and going downstairs.
23 Citations
10 Claims
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1. A method for estimating a body pose in a body pose detection module provided with a triaxial accelerometer within a wireless sensor network of a plurality of body pose detection modules arranged to detect and simultaneously monitor body poses of multiple users, the method comprising steps of:
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performing signal pre-processing of a triaxial acceleration signal readout from the triaxial accelerometer at the body pose detection module attached to a user body so as to abstract a dynamic acceleration and a static acceleration of the triaxial acceleration signal; determining whether the dynamic acceleration of the triaxial acceleration signal is abnormal indicating that a body pose is a falling pose; and when the dynamic acceleration of the triaxial acceleration signal is not abnormal, analyzing the dynamic acceleration of the triaxial acceleration signal to determine whether a body pose is one of a static pose and a dynamic pose, wherein the signal preprocessing is performed by; sampling from the triaxial acceleration signal readout from the triaxial accelerometer, each of sensing axes collecting 256 acceleration data, with a sampling frequency of 128 Hz and performing the signal pre-processing once at every two seconds; subjecting acceleration data of the sensing axes of the triaxial acceleration signal to an eight-layer Haar wavelet transform; maintaining a wavelet transform coefficient of the eight-layer Haar wavelet transform with a lowest frequency, while omitting other wavelet transform coefficients; converting the wavelet transform coefficient of the lowest frequency into a time domain to represent the static acceleration of the triaxial acceleration signal; and subtracting the static acceleration from the triaxial acceleration signal to obtain the dynamic acceleration of the triaxial acceleration signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification