Samarasinghe Prasanga N, Abhayapala Thushara D, Lu Yan, Chen Hanchi, Dickins Glenn
Audio and Acoustic Signal Processing Group, Research School of Engineering, Australian National University, Canberra, Australia.
Dolby Laboratories, Sydney, Australia.
J Acoust Soc Am. 2018 Sep;144(3):1381. doi: 10.1121/1.5053579.
Allen and Berkley's image source method (ISM) is proven to be a very useful and popular technique for simulating the acoustic room transfer function (RTF) in reverberant rooms. It is based on the assumption that the source and receiver of interest are both omnidirectional. With the inherent directional nature of practical loudspeakers and the increasing use of directional microphones, the above assumption is often invalid. The main objective of this paper is to generalize the frequency domain ISM in the spherical harmonics domain such that it could simulate the RTF between practical transducers with higher-order directivity. This is achieved by decomposing transducer directivity patterns in terms of spherical harmonics and by applying the concept of image sources in spherical harmonics based propagation patterns. Therefore, from now on, any transducer can be modeled in the spherical harmonics domain with a realistic directivity pattern and incorporated with the proposed method to simulate room acoustics more accurately. We show that the proposed generalization also has an alternate use in terms of enabling RTF simulations for moving point-transducers inside pre-defined source and receiver regions.
艾伦和伯克利的镜像源方法（ISM）被证明是一种非常有用且流行的技术，用于模拟混响室内的声学房间传递函数（RTF）。它基于这样的假设：感兴趣的声源和接收器都是全向的。鉴于实际扬声器固有的方向性以及定向麦克风的使用日益增加，上述假设往往是无效的。本文的主要目标是在球谐域中推广频域ISM，以便它能够模拟具有高阶方向性的实际换能器之间的RTF。这是通过根据球谐函数分解换能器方向性图案，并在基于球谐函数的传播图案中应用镜像源概念来实现的。因此，从现在起，任何换能器都可以在球谐域中用逼真的方向性图案进行建模，并与所提出的方法相结合，以更准确地模拟室内声学。我们表明，所提出的推广在为预定义源和接收器区域内的移动点换能器进行RTF模拟方面也有另一种用途。
