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Modified GSC method to reduce the distortion of an enhanced signal using cross-correlation and sidelobe neutralization

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Abstract
The generalized sidelobe canceller (GSC) method is a common algorithm to enhance audio signals using a microphone array. Distortion of the enhanced audio signal consists of two parts: the residual acoustic noise and the distortion of the desired audio signal, which means that the desired audio signal is damaged. This thesis proposes a modified GSC method to reduce both kinds of distortion when the desired audio signal is a non‐stationary speech signal. First, the cross‐correlation coefficient between the canceling signal and the error signal of the least mean square (LMS) algorithm was added to the adaptive process of the GSC method to reduce the distortion of the enhanced signal while the energy of the desired signal frame was increased suddenly. The sidelobe pattern of beamforming was then presented to estimate the noise signal in the beamforming output signal of the GSC method. The noise component of the beamforming output signal was decreased by subtracting the estimated noise signal to improve the denoising performance of the GSC method. Finally, the GSC‐SN‐MCC method was proposed by merging the above two methods. The experiment was performed in an anechoic chamber to validate the proposed method in various SNR conditions. Furthermore, the simulated calculation with inaccurate noise directions was conducted based on the experiment data to inspect the robustness of the proposed method to the error of the estimated noise direction. The experiment data and calculation results indicated that the proposed method could reduce the distortion effectively under various SNR conditions and would not cause more distortion if the estimated noise direction is far from the actual noise direction.
Author(s)
서항
Issued Date
2022
Awarded Date
2022-02
Type
dissertation
URI
https://oak.ulsan.ac.kr/handle/2021.oak/9802
http://ulsan.dcollection.net/common/orgView/200000602344
Affiliation
울산대학교
Department
일반대학원 기계자동차공학과
Advisor
이장명
Degree
Doctor
Publisher
울산대학교 일반대학원 기계자동차공학과
Language
eng
Rights
울산대학교 논문은 저작권에 의해 보호 받습니다.
Appears in Collections:
Mechanical & Automotive Engineering > 2. Theses (Ph.D)
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