Directional Sources and Listeners in Interactive Sound Propagation using Reciprocal Wave Field Coding

摘要

Common acoustic sources, like voices or musical instruments, exhibit strongfrequency and directional dependence. When transported through complexenvironments, their anisotropic radiated field undergoes scattering, diffraction,and occlusion before reaching a directionally-sensitive listener. Wepresent the first wave-based interactive auralization system that encodes and renders a complete reciprocal description of acoustic wave fields ingeneral scenes. Our method renders directional effects at freely moving androtating sources and listeners and supports any tabulated source directivityfunction and head-related transfer function. We represent a static scene’sglobal acoustic transfer as an 11-dimensional bidirectional impulse response(BIR) field, which we extract from a set of wave simulations. We parametricallyencode the BIR as a pair of radiating and arriving directions for theperceptually-salient initial (direct) response, and a compact 6 × 6 reflectionstransfer matrix capturing indirect energy transfer with scene-dependentanisotropy. We render our encoded data with an efficient and scalable algorithm– integrated in the Unreal EngineTM – whose CPU performance isagnostic to scene complexity and angular source/listener resolutions. Wedemonstrate convincing effects that depend on detailed scene geometry, fora variety of environments and source types.