A Novel Method for Speech Acquisition and Enhancement by 94 GHz Millimeter-Wave Sensor

Sensors

Fuming Chen¹  Sheng Li²  Chuantao Li¹  Miao Liu¹  Zhao Li¹  Huijun Xue¹  Xijing Jing¹  Jianqi Wang¹ 

[1] Department of Biomedical Engineering, Fourth Military Medical University, Xi’an 710032, China;College of Control Engineering, Xijing University, Xi’an 710123, China;

关键词: radar speech;    94 GHz MMW;    speech enhancement;    empirical mode decomposition;    mutual information entropy;   

DOI  :  10.3390/s16010050

来源: mdpi

【 摘 要 】

In order to improve the speech acquisition ability of a non-contact method, a 94 GHz millimeter wave (MMW) radar sensor was employed to detect speech signals. This novel non-contact speech acquisition method was shown to have high directional sensitivity, and to be immune to strong acoustical disturbance. However, MMW radar speech is often degraded by combined sources of noise, which mainly include harmonic, electrical circuit and channel noise. In this paper, an algorithm combining empirical mode decomposition (EMD) and mutual information entropy (MIE) was proposed for enhancing the perceptibility and intelligibility of radar speech. Firstly, the radar speech signal was adaptively decomposed into oscillatory components called intrinsic mode functions (IMFs) by EMD. Secondly, MIE was used to determine the number of reconstructive components, and then an adaptive threshold was employed to remove the noise from the radar speech. The experimental results show that human speech can be effectively acquired by a 94 GHz MMW radar sensor when the detection distance is 20 m. Moreover, the noise of the radar speech is greatly suppressed and the speech sounds become more pleasant to human listeners after being enhanced by the proposed algorithm, suggesting that this novel speech acquisition and enhancement method will provide a promising alternative for various applications associated with speech detection.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.