基于灰色Verhulst模型的音频频带扩展方法

Audio Bandwidth Extension Method Based on Grey Verhulst Model

受到传输带宽的限制,宽带音频的自然度和听觉质量会有所下降,因此,本文提出了一种基于灰色Verhulst模型的宽带向超宽带音频频带扩展方法.根据音频信号频谱包络序列的演变趋势,采用灰色Verhulst模型对高频频谱包络进行估计,并利用最近邻匹配方法对高频频谱细节进行预测,最后经过高频频谱包络的调整,所提方法能够有效地恢复7～14kHz频率范围内的高频成分.主客观测试表明,该方法改善了宽带音频的听觉质量,并且优于传统的基于高斯混合模型的音频频带扩展方法.

The naturalness and auditory quality of the wideband audio is generally degraded due to the limitation of transmis- sion bandwidth, so this paper presents a kind of audio bandwidth extension method from the wideband to super wideband based on grey Verhulst model. Grey Verhulst model was utilized for estimating the envelope of high-frequency spectrum, according to the evolution tendency of the spectral envelope series of audio signals. In addition, nearest-neighbor matching was utilized to predict the fine structure of high-frequency components. At last, the proposed method can effectively recover the high-frequency components in the frequency range 7-14 kHz through the envelope adjusanent of high-frequency spectrum. Subjective and objective testing results indicate that the proposed method can improve the auditory quality of the wideband audio and outperforms the conventional method of audio bandwidth extension based on Gaussian mixture model.