Detection and Classification of Finer-Grained Human Activities Based on Stepped-Frequency Continuous-Wave Through-Wall Radar.
The through-wall detection and classification of human activities are critical for anti-terrorism, security, and disaster rescue operations. An effective through-wall detection and classification technology is proposed for finer-grained human activities such as piaffe, picking up an object, waving, jumping, standing with random micro-shakes, and breathing while sitting. A stepped-frequency continuous wave (SFCW) bio-radar sensor is first used to conduct through-wall detection of finer-grained human activities; Then, a comprehensive range accumulation time-frequency transform (CRATFR) based on inverse weight coefficients is proposed, which aims to strengthen the micro-Doppler features of finer activity signals. Finally, in combination with the effective eigenvalues extracted from the CRATFR spectrum, an optimal self-adaption support vector machine (OS-SVM) based on prior human position information is introduced to classify different finer-grained activities. At a fixed position (3 m) behind a wall, the classification accuracies of six activities performed by eight individuals were 98.78% and 93.23%, respectively, for the two scenarios defined in this paper. In the position-changing experiment, an average classification accuracy of 86.67% was obtained for five finer-grained activities (excluding breathing) of eight individuals within 6 m behind the wall for the most practical scenario, a significant improvement over the 79% accuracy of the current method.
Department of Medical Electronics, School of Biomedical Engineering, Fourth Military Medical University, Xi'an 710032, China. qifgbme@outlook.com.
Fugui
F
Qi
Department of Medical Electronics, School of Biomedical Engineering, Fourth Military Medical University, Xi'an 710032, China. liangfulai@fmmu.edu.cn.
Fulai
F
Liang
Department of Medical Electronics, School of Biomedical Engineering, Fourth Military Medical University, Xi'an 710032, China. fmmulvhao@fmmu.edu.cn.
Hao
H
Lv
Department of Medical Electronics, School of Biomedical Engineering, Fourth Military Medical University, Xi'an 710032, China. chuantaoli@hotmail.com.
Chuantao
C
Li
Department of Medical Electronics, School of Biomedical Engineering, Fourth Military Medical University, Xi'an 710032, China. fumingfmmu@outlook.com.
Fuming
F
Chen
Department of Medical Electronics, School of Biomedical Engineering, Fourth Military Medical University, Xi'an 710032, China. wangjq@fmmu.edu.cn.
Jianqi
J
Wang
comprehensive range accumulation; finer-grained human activity; human micro-Doppler; support vector machine; through-wall