Geometrical acoustics is well suited for simulating room reverberation in interactive real-time applications. While the image source model (ISM) is exceptionally fast, the restriction to specular reflections impacts its perceptual plausibility. To account for diffuse late reverberation, hybrid approaches have been proposed, e.g., using a feedback delay network (FDN) in combination with the ISM. Here, a computationally-efficient, digital-filter approach is suggested to account for effects of non-specular reflections in the ISM and to couple scattered sound into a diffuse reverberation model using a spatially rendered FDN. Depending on the scattering coefficient of a room boundary, energy of each image source is split into a specular and a scattered part which is added to the diffuse sound field. Temporal effects as observed for an infinite ideal diffuse (Lambertian) reflector are simulated using cascaded all-pass filters. Effects of scattering and multiple (inter-) reflections caused by larger geometric disturbances at walls and by objects in the room are accounted for in a highly simplified manner. Using a single parameter to quantify deviations from an empty shoebox room, each reflection is temporally smeared using cascaded all-pass filters. The proposed method was perceptually evaluated against dummy head recordings of real rooms.

翻译：几何声学非常适合用于交互式实时应用中的房间混响模拟。虽然镜像源模型（ISM）速度极快，但仅考虑镜面反射会限制其感知逼真度。为模拟漫射晚混响，已有研究提出混合方法（例如，将反馈延迟网络（FDN）与ISM结合使用）。本文提出一种计算高效的数字滤波器方法，以处理ISM中非镜面反射的影响，并通过空间渲染的FDN将散射声耦合到漫射混响模型中。根据房间边界的散射系数，每个镜像源的能量被分为镜面部分和散射部分，后者被添加到漫射声场中。针对无限理想漫射（朗伯）反射体观测到的时间效应，采用级联全通滤波器进行模拟。对于由墙壁较大几何扰动及房间内物体引起的散射和多重（相互）反射效应，本文以高度简化的方式进行建模。通过单一参数量化空鞋盒房间的偏差，每个反射的时间拖尾使用级联全通滤波器实现。该方法通过真实房间的假头录音进行了感知评估。