Sound analysis, sound synthesis, and sound processing for audio and musical applications

本研究项目旨在利用信号处理技术的最新进展，提高音频信号表示和建模的准确性和充分性。更准确地说，目标是更好地解决声音信号的双重性质，声音信号通常是暂时瞬态和调制频率成分的混合物。这将提高声音处理、声音合成的质量，并将培育高质量声源分离或音频变形等应用项目。这个项目是所谓的分析/合成方法的一部分，用于声音合成和声音处理，这是一种在音乐应用中经常使用的方法，也用于声音设计，音频编码和录音。分析/合成的基本目标是构想相关模型，通过一组控制合成结构的时间函数（控制参数）来表示声学信号。这些时间函数可以在抽象中生成，也可以在分析过程中从预先录制的声音中提取。重新合成产生的信号在感知上与原始声音相同。通过修改和替换控制参数，该分析/合成方案可以提供非常精细和精确的声音材料处理。例如，它可以让一个人产生一组合成声音信号，这些信号来源于一个单一的原始声音信号，或者在两个关键声音之间进行变形。它还可以通过对时间函数进行适当的排序和分组来决定源分离。我们计划对复调信号的部分的时变参数进行更一般和更高层次的描述，并开发互补的分析技术。我们还希望为音频源分离提供更好的策略，这将受益于声音信号底层结构的先验知识，特别是关于相位的知识。最后，将分析/合成方法扩展到某些非线性系统将有助于对声音合成和声音处理有更统一的看法，并将允许几种现有音频效果的一般表示。除了知识的进步和高素质人员的培训之外，在应用方面的预期意义是，更好的分析/合成程序将导致更精细的合成和加工方法。更具体地说，这种改进在分离几个声源有用的应用程序中可能是决定性的，例如用于录音、音频恢复、编码、游戏行业和电影音效的高级混音。这也将有助于设计工业应用中涉及复杂声音的混合，如“环境声音”（滚动，球，风，水和电机的声音）。

This research project aims at improving the accuracy and the adequacy of audio signal representations and modelling by benefiting from recent advances in signal processing techniques. More precisely the goal is to better address the dual nature of sound signals, which are often a mixture of temporal transients, and modulated frequency components. It will result in a better quality of sound processing, sound synthesis, and will nurture applied projects such as high-quality sound source separation or audio morphing.This project is part and parcel of the so-called analysis/synthesis approach for sound synthesis and sound processing, an often-used approach in musical applications, but also in sound design, audio coding and sound recording. The basic goal of analysis/synthesis is to conceive relevant models to represent acoustical signals by a set of temporal functions (the control parameters) that controls a synthesis structure. These temporal functions can be generated in the abstract or extracted from a pre-recorded sound during the analysis process. Re-synthesis produces a signal that sounds perceptually identical to the original sound. By modifying and substituting control parameters, this analysis/synthesis scheme can provide for very refined and precise processing of sound material. For example, it may allow one to produce a family of synthetic sound signals derived from a single original one or to carry out a morphing between two key sounds. It can also be used to make a decision on source separation by a proper sorting and grouping of temporal functions into coherent subsets.We plan to put in place a more general and higher-level description of time-varying parameters of the partials of polyphonic signals, and develop complementary analyses techniques. We also hope to provide better strategies for audio source separation that will benefit from prior knowledge of the underlying structure of sound signals, particularly as regards the phase. Finally, the extension of the analysis/synthesis approach to some classes of non-linear-systems will contribute to a more unified view of sound synthesis and sound processing and will allow for a general representation of several existing audio effects. Beyond the advance of knowledge and the training of highly qualified personnel, the expected significance in terms of applications is that a better analysis/synthesis procedure would lead to refined synthesis and processing methods. More specifically, this refinement could be decisive in applications where the separation of a few sound sources is useful, such as advanced remix for sound recording, audio restoration, coding, game industry, and movie sound effects. It would also help to design industrial applications which involve mixture of complex sounds such as 'environmental sounds' (rolling, balls, wind, water, and motor sounds).