Auralization of Urban Environments - Real-time Simulation of Diffraction

在DFG和FAPERJ征求建议书的范围内，巴西的一个研究小组(UFRJ，里约热内卢联邦大学)和一个德国的研究小组(RWTH，Rheinisch-Westfälische Technische Hochschule Aachen)申请了一个联合项目。这项提议的目标是在噪声传播和评估的应用中实现3D声音模拟(可听化)的先进方法：城市环境的可听化。特别是，这家德国集团将主要专注于城市环境中声音绕射的实时模拟。模拟方法将以几何声学为基础。它指的是标准噪声映射计算，但它将通过有限边缘上的频率相关绕射来扩展已建立的过程，该过程表示为数字滤波器。第一步是基于场景几何体识别主要传播路径。专注于这些贡献将减少从分析模型(毕奥-托尔斯泰、梅德温、斯文森等)推导衍射滤光片的计算工作量。将通过实施近似来有效地模拟绕射(Maekawa、UTD、Svensson等)来实施控制计算工作的策略。这些基本绕射对象在同样的基本操作中都有它们的算法计数器，使用共享内存并行化将有效地解决这些问题。将这些基本计算分发到可用资源(多核处理器的单元、PC集群的节点)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。通过将这些格式整合为声音传播模拟和可听化的基础，已经存在的数据可以直接使用(例如，地籍地图和大城市的数字表示)。巴西研究团队还将重点放在适当的视觉捕捉和声音记录城市动态上。在共同努力下，巴西和德国的成绩将最终进行评估，并使用亚琛和里约热内卢截然不同的城市模型和噪音情况进行数字和心理声学比较。

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.