关键词: 语音增强, 双谱分析, 特征耦合, 高阶非线性, 跳跃连接

Abstract: Most existing time-frequency domain speech enhancement methods rely on short-time Fourier transform (STFT) and use second-order spectral statistics to model the linear characteristics of signals, while neglecting the potential high-order nonlinear interactions in speech. This paper proposes a speech enhancement method based on bispectrum nonlinear feature coupling. The method adopts an encoder-decoder architecture and introduces a bispectrum feature extraction module after the encoder to capture phase coupling and nonlinear structural information revealed by third-order statistics. A skip connection mechanism is used to fuse the bispectral and encoder features, enabling deeper modeling of both amplitude and phase. Experimental results on the VoiceBank+DEMAND dataset show that the proposed method achieves a Perceptual Evaluation of Speech Quality (PESQ) score of 3.57, representing a 15.53% improvement over the baseline. Furthermore, it achieves relative gains of 5.51%, 3.08%, and 10.31% on the Mean Opinion Score for Signal Distortion (CSIG), Background Noise Intrusiveness (CBAK), and Overall Speech Quality (COVL), respectively.

Key words: speech enhancement, bispectral analysis, feature coupling, higher-order nonlinearity, skip connections