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Entropy 2016, 18(7), 265; doi:10.3390/e18070265

Noise Suppression in 94 GHz Radar-Detected Speech Based on Perceptual Wavelet Packet

1,†
,
1,2,†
,
1
,
1
,
1
,
3,* and 1,4,*
1
Department of Biomedical Engineering, Fourth Military Medical University, Xi’an 710032, China
2
Laboratory of Aviation Medicine, Naval Medical Research Institute, Shanghai 200433, China
3
College of Control Engineering, Xijing University, Xi’an 710123, China
4
Department of Physics and Information Engineering, Shaanxi University of Technology, Hanzhong 723001, China
These authors contributed equally to this work.
*
Authors to whom correspondence should be addressed.
Academic Editor: Carlo Cattani
Received: 12 April 2016 / Revised: 4 July 2016 / Accepted: 13 July 2016 / Published: 19 July 2016
(This article belongs to the Special Issue Wavelets, Fractals and Information Theory II)
View Full-Text   |   Download PDF [2644 KB, uploaded 19 July 2016]   |  

Abstract

A millimeter wave (MMW) radar sensor is employed in our laboratory to detect human speech because it provides a new non-contact speech acquisition method that is suitable for various applications. However, the speech detected by the radar sensor is often degraded by combined noise. This paper proposes a new perceptual wavelet packet method that is able to enhance the speech acquired using a 94 GHz MMW radar system by suppressing the noise. The process is as follows. First, the radar speech signal is decomposed using a perceptual wavelet packet. Then, an adaptive wavelet threshold and new modified thresholding function are employed to remove the noise from the detected speech. The results obtained from the speech spectrograms, listening tests and objective evaluation show that the new method significantly improves the performance of the detected speech. View Full-Text
Keywords: radar-detected speech; 94 GHz MMW radar; speech enhancement; perceptual wavelet packet; thresholding function radar-detected speech; 94 GHz MMW radar; speech enhancement; perceptual wavelet packet; thresholding function
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MDPI and ACS Style

Chen, F.; Li, C.; An, Q.; Liang, F.; Qi, F.; Li, S.; Wang, J. Noise Suppression in 94 GHz Radar-Detected Speech Based on Perceptual Wavelet Packet. Entropy 2016, 18, 265.

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