从带宽有限音频信号生成带宽扩展信号的设备和方法
【技术领域】
[0001] 本发明涉及音频信号处理，具体涉及用于从带宽有限音频信号生成带宽扩展信号 的设备和方法。
【背景技术】
[0002] 音频信号的存储或传输常常受到严格的比特率约束的影响。过去，当仅 极低的比特率可用时，编码者被迫大幅度地减少要传送的音频带宽。现在，现代音 频编解码器可以通过使用带宽扩展（BWE)方法来对宽带信号进行编码，这些带宽 扩展方法如下所述：M. Dietz, L.Liljeryd，K.Kj6rlillgand 0. Kunz, "Spectral Band Rep 1ication，a novel approach in audio coding，" in 112th AES Convention, Munich, May 2002 ；S. Meltzer, R. Bdhm and F.Henn,uSBR enhanced audio codecs for digital broadcasting such as "Digital Radio Mondiale"（DRM)，"in 112th AES Convention, Munich,May 2002 ；T. Ziegler, A. Ehret,P.Ekstrand and M.Lutzky, "Enhancing mp3with SBR:Features and Capabilities of the new mp3PR0 Algorithm，''in 112th AES Convention, Munich, May 2002 international Standard ISO/ IEC 14496-3:2001/FPDAM 1，"Bandwidth Extension，"IS0/IEC，2002. Speech bandwidth extension method and apparatus,Vasu Iyengar et al ；E. Larsen, R. M. Aarts, and M. Danessis. Efficient high-frequency bandwidth extension of music and speech. In AES 112th Convention, Munich, Germany, May 2002 ；R.M. Aarts, E. Larsen, and 0.0 uweltjes. A unified approach to low-and high frequency bandwidth extension. In AES 115th Convention, New York, USA, October 2003 ；K. KSyhko, A Robust Wideband Enhancement for Narrowband Speech Signal. Research Report, Helsinki University of Technology,Laboratory of Acoustics and Audio Signal Processing, 2001 ；E.Larsen and R. M. Aarts. Audio Bandwidth Extension-Application to psychoacoustics, Signal Processing and Loudspeaker Design.John Wiley&Sons, Ltd, 2004 ；E.Larsen, R. M.Aarts, and M.Danessis. Efficient high-frequency bandwidth extension of music and speech.In AES 112th Convention, Munich, Germany, May 2002 ； J.Makhoul. Spectral Analysis of Speech by Linear Prediction.IEEE Transactions on Audio and Electroacoustics，AU-21 (3)，June 1973 ；United States Patent Application08/951，029,Ohmori，et al.,Audio band width extending system and method ；and United States Patent 6895375,Malah, D&Cox, R. V. :System for bandwidth extension of Narrow-band speech?这些算法依赖于高频成分（HF)的 参数表现，该高频内容借助于移项进入高频频谱区（"修补"）和参数驱动的后处理 的应用而从解码信号的低频部分（LF)生成。该低频部分使用任何音频或语音编码 器来编码。例如，带宽扩展方法如下所述：M. Dietz, L. Lil jeryd，K.K.j6rlingand 0. Kunz, "Spectral Band Replication, a novel approach in audio coding，" in 112th AES Convention, Munich, May 2002 ；S. Meltzer, R. Bdhm and F. Henn, USBR enhanced audio codecs for digital broadcasting such as"Digital Radio Mondiale"(DRM)，''in 112th AES Convention, Munich,May 2002 ；T. Ziegler, A. Ehret,P.Ekstrand and M.Lutzky, "Enhancing mp3with SBR:Features and Capabilities of the new mp3PR0 Algorithm，''in 112th AES Convention, Munich, May 2002 ；and International Standard IS0/IEC14496-3:2001/FPDAM l，"Bandwidth Extension， "IS0/IEC，2002。由 Vasu Iyengar 等人所提出的语音带宽扩展方法和设备依赖于单边带调制（SSB)，其也常被称为"复制"方 法，用于生成多重HF修补。
[0003] 近来，一种新的算法，其使用一组相位声码器（a bank of phase vocoders)，如下 所述：M. Puckette. Phase-locked Vocoder. IEEE ASSP Conference on Applications of Signal Processing to Audio and Acoustics, Mohonk 1995,，Robel,A.:Transient detection and preservation in the phase vocoder ；citeseer. ist. psu. edu/679246. html ；Laroche L. , Dolson M. : "Improved phase vocoder timescale modification of audio"，IEEE Trans. Speech and Audio Processing, vol. 7, no. 3, pp. 323 -332 ；United States Patent 6549884,Laroche,J. &Dolson, M. :Phase-vocoder pitch-shifting, for the generation of the different patches, has been presented as described in Frederik Nagel, Sascha Disch，"A harmonic bandwidth extension method for audio codecs，" ICASSP International Conference on Acoustics, Speech and Signal Processing，IEEE CNF，Taipei，Taiwan，Apri 12009D此方法已被开发以避免听觉粗糙度， 其常常在处于SSB带宽扩展中的信号中被观察到。虽然此方法有助于许多音调信号，但这 个被称为"谐波带宽扩展" 01BE)的方法容易使包含在音频信号中的瞬态生成质量上的下 降，如下所述：Frederik Nagel，Sascha Disch，Nikolaus Rettelbach，"A phase vocoder driven bandwidth extension method with novel transient handling for audio codecs，"126th AES Convention，Munich，Germany，May 2009。这是因为无法保证子带上的 垂直相干被保存在标准相位声码器算法中，此外，相位的重新计算必需被执行于转变或替 代的滤波器组的时间块上。因此，针对包括瞬态的信号部分需要有特别的处理。此外，应用 于HBE算法中的基于相位声码器的重叠相加造成额外的延迟，该额外的延迟太高以至于无 法被针对通讯目的而设计的应用所接受。
[0004] 如上所述，现有的带宽扩展方案可以一次在给定的信号块上应用一种修补 方法，如基于修补的SSB或基于相位声码器技术的SSB，修补如下所述Dietz，L. Liljeryd, K.Kjorlingand 0. Kunz, "Spectral Band Replication, a novel approach in audio coding，" in 112th AES Convention, Munich, May 2002 ；S. Meltzer, R. B〇hm and F. Henn, "SBR enhanced audio codecs for digital broadcasting such as ^Digital Radio Mondial(DRM), ^ in 112th AES Convention, Munich, May 2002； T.Ziegler,A. Ehret, P. Ekstrand and M. Lutzky, ^Enhancing mp3with SBR:Features and Capabilities of the new mp3PR0 Algorithm，" in 112th AES Convention, Munich, May 2002 ;and International Standard IS0/IEC14496_3:2001/FPDAM 1， "Bandwidth Extension，" ISO/IEC，2002. Speech bandwidth extension method and apparatus, Vasu Iyengar et al. , or HBE vocoder based patching explained in Frederik Nagel, Sascha Disch，"A harmonic bandwidth extension method for audio codecs，" in ICASSP International Conference on Acoustics, Speech and Signal Processing,IEEE CNF，Taipei，Taiwan，April 2009?相位声码器技术如下所述：M. Puckette. Phase-locked Vocoder. IEEE ASSP Conference on Applications of Signal Processing to Audio and Acoustics, Mohonk 1995. "，R6bel,A.:Transient detection and preservation in the phase vocoder ；citeseer. ist. psu. edu/679246. html ；Laroche L，Dolson M. Improved phase vocoder timescale modification of audio"，IEEE Trans. Speech and Audio Processing,