STUDIES OF HUMAN SOUND LOCALIZATION

对许多生物来说，声音定位是一个生存问题。 为 人类，这样的说法将是言过其实。 但是， 否定了声音定位在人类生活中的重要性。 它有助于 我们在嘈杂的环境中分离目标和竞争信息的能力 环境，这是正常通信的重要组成部分。 当这种能力下降时，就像许多类型的听力损失一样， 通信严重中断。 长期目标是 项目是一个完整的了解机制和过程， 人类声音定位。 广泛的研究表明， 声音的位置由三个主要的声学线索确定： 耳间时间差、耳间水平差和耳廓 过滤效果。 在某些情况下，一个或多个 提示可能是模糊的或不可靠的，例如收听窄带 声音或不熟悉的声音。 在这些情况下，侦听器必须使用 附加线索或不同地加权主要线索。 的一大重点 这个项目是提取和使用额外的线索， 替代加权策略。 具体而言，该项目将 研究来自头部小动作的定位线索的使用 以及听众对特定的知识或期望的作用 刺激特性 在拟议的实验中， 将估计声音的明显位置，无论是在一个自由的 声场或虚拟自由场， 通过耳机合成声音。 在虚拟自由场，头部位置 用磁跟踪器监测， 在真实的时间内适当地修改。 一个听众的知识或 对刺激的期望是通过改变两者之间的关系来操纵的- 刺激和刺激谱的刺激内方差。 额外 实证研究将调查的刺激功能，支配 听觉空间中的单个源的可分离性。 在这末后 实验中，听众将指出两个明显的位置， 虚拟自由场中的独立源。 刺激参数，如 振幅包络相干性、起始-偏移距相干性和频谱相干性 重叠将被操纵，以评估其重要性， 源隔离。 除了实证工作外，该项目还将 评估声音定位的神经网络模型。 该模型是一个 基于径向基的单隐藏层、单输出层网络 功能架构 神经网络模型是有吸引力的，因为 训练和学习，这被认为是重要的人类声音 本地化，明确纳入模型。

For many organisms sound localization is a matter of survival. For humans, such a claim would be an overstatement. However, there can be no denying the importance of sound localization in human life. It subserves our ability to segregate target and competing messages in noisy environments, which is an essential component of normal communication. When that ability is degraded, as with many types of hearing loss, communication is significantly disrupted. The long-term goal of this project is a complete understanding of the mechanisms and processes of human sound localization. Extensive research suggests that the apparent position of a sound is determined by three primary acoustical cues: interaural time differences, interaural level differences, and pinna filtering effects. There are circumstances in which one or more of the cues may be ambiguous or unreliable, such as listening to a narrowband sound or to an unfamiliar sound. In these cases listeners must either use additional cues or weight the primary cues differently. A major focus of this project is the extraction and use of the additional cues, and the alternative weighting strategies. Specifically, the project will investigate the use of localization cues derived from small head movements and the role of a listener's knowledge of or expectations about specific stimulus characteristics. In the proposed experiments human listeners will estimate the apparent positions of sounds presented in either a free sound field or the virtual free-field produced by delivering computer- synthesized sound over headphones. In virtual free-field, head position is monitored with a magnetic tracker so that the stimuli can be appropriately modified in real time. A listener's knowledge of or expectations about the stimuli is manipulated by changing the between- stimuli and within-stimulus variance of the stimulus spectrum. Additional empirical studies will investigate the stimulus features that govern the separability of individual sources in auditory space. In these latter experiments, listeners will indicate the apparent positions of two independent sources in a virtual free-field. Stimulus parameters such amplitude envelope coherence, onset-offset asynchrony, and spectral overlap will be manipulated to assess their importance for successful source segregation. In addition to the empirical work, the project will evaluate a neural network model of sound localization. The model is a single hidden-layer, single output layer network based on a radial basis function architecture. Neural network models are attractive since training and learning, which are thought to be important in human sound localization, are explicitly incorporated in the models.