Auralization of Urban Environments - Real-time Simulation of Diffraction

在DFG和FAPERJ的提案征集中，巴西的一个研究小组（UFRJ，里约热内卢联邦大学）和德国的一个研究小组（RWTH，Rheinisch-Westfälische Technische Hochschule亚琛）申请了一个联合项目。该提案的目的是在噪声传播和评估应用中实现3D声音模拟（可听化）的先进方法：城市环境的可听化。特别是，德国小组将主要关注城市环境中声音衍射的实时模拟。模拟方法将基于几何声学。它指的是标准的噪声映射计算，但它将通过表示为数字滤波器的有限边缘处的频率相关衍射来扩展已建立的程序。第一步是根据场景几何形状确定主要传播路径。集中于这些贡献将减少从分析模型（Biot-Tolstoy，Medwin，Svensson等）导出衍射滤波器的计算工作量。一种控制计算工作的策略将通过实施近似来有效地模拟衍射（Maekawa，UTD，Svensson等）。这些基本的衍射对象在同样的基本操作中具有它们的算法对应部分，这将使用共享存储器并行化来有效地解决。这些基本计算到可用资源（多核处理器的单元、PC集群的节点）的分布处理需要智能调度。为了简化几何输入数据的交换，德国和巴西的研究人员将确定现有的数据格式，如CityGML。通过整合这些格式作为声音传播模拟和可听化的基础，可以直接使用现有数据（例如地籍图和大城市的数字表示）。巴西研究小组还将重点关注适当的视觉捕捉和声学记录城市动态。在一项共同努力中，将对巴西和德国的成果进行最终评估，并利用亚琛和里约热内卢非常不同的城市模型和噪音情况，从数字和心理声学上进行比较。

Within the call for proposals from DFG and FAPERJ, a research group from Brazil (UFRJ, Universidade Federal Rio de Janeiro) and a research group from Germany (RWTH, Rheinisch-Westfälische Technische Hochschule Aachen) apply for a joint project. The objective of this proposal is an advanced methodology to achieve a 3D sound simulation (auralization) in the application of noise propagation and assessment: Auralization of Urban Environments. In particular, the German group will mainly focus on real-time simulation of sound diffraction in urban environments. The simulation methodology will be based on Geometrical Acoustics. It refers to standard noise mapping calculations but it will extend the established procedures by frequency-dependent diffraction at finite edges represented as digital filters. The first step will be identifying the major propagation paths based on a scene geometry. Concentrating on these contributions will decrease the computational effort to derive diffraction filters from analytic models (Biot-Tolstoy, Medwin, Svensson, etc.). A strategy to control the computation efforts will be pursued by implementing approximations to efficiently model diffraction (Maekawa, UTD, Svensson, etc.). These basic diffraction objects have their algorithmic counter parts in likewise basic operations, which will be solved efficiently using shared-memory parallelization. The distribution handling of these basic calculations to the available resources (units of a multicore processor, nodes of a PC-cluster) require intelligent scheduling. In order to simplify the exchange of geometrical input data, the German and Brazilian researchers will settle on established data formats, such as CityGML. By making it possible to integrate these formats as basis for the sound propagation simulation and auralization, already existing data can be used directly (e.g. cadastral maps and digital representations of large cities). The Brazilian research team will also focus on appropriately visually capturing and acoustically recording urban dynamics. In a joint effort, the results of the Brazilian and German accomplishments will be finally evaluated and compared numerically and psycho-acoustically using both the very different city models and noise situations in Aachen and Rio de Janeiro.