利用自相关函数和双耳自相关函数分析对交通噪声特征参量的提取~

对实地双通道测量获得的道路交通噪声和铁路噪声信号样本进行了自相关函数和双耳自相关函数(Interaural CrossCorrelation Function)的分析。进而通过对噪声样本时间因子和空间因子的相关性分析、主成分分析和主观评价实验,得到了3个铁路噪声源特征参量物理因子和4个道路交通噪声源特征参量物理因子。发现与传统的声压级测量相比,表征声音信号时间特性和空间特性的这7个物理量可以更全面、准确地表征交通噪声的特性。在对道路噪声进行测量或分析时,掌握与声源视觉宽度和音调感相对应的物理因子以及双耳时延和初始能量,就可获悉与人的主观评价相一致的道路交通噪声特征信息;对铁路噪声而言,掌握与声源视觉宽度相对应的物理因子以及双耳时延和声音的重复性特征,就可以得到与入主观评价相一致的铁路噪声特征信息。综合道路噪声特征参量和铁路噪声特征参量可以发现,双耳时延和与声源视觉宽度相对应的物理因子是与人的主观反应最为一致的主成分指标,说明噪声中决定人的评价的最主要的因素是代表空间特征的信号因子。

Parameter extraction of traffic noise by analysis of auto-correlation function and interaural cross-correlation function

Analysis on auto-correlation function and interaural cross-correlation function of road traffic noise and railway noise recorded by using dummy head on the spot was carried out. 3 representative parameters for railway noise and 4 representative parameters for road traffic noise were obtained through correlation analysis, principal component analysis and subjective evaluation experiment. It was shown that comparing with traditional noise level measurement, 7 factors that mean the temporal factors extracted from autocorrelation function analysis and spatial factors extracted from interaual cross-correlation function analysis could represent the acoustical information of traffic noise more adequately and accurately. In the process of measurement and analysis on road traffic noise, if the physical factors relevant to subjective diffuseness of noise field and pitch, interaural time delay for the horizontal angle, and energy represented at the origin of the delay were obtained, the basic signal information of road traffic noise that was consistent with subjective noise annoyance evaluation could be grasped thoroughly. The same for railway noise, its basic signal information consistent with subjective noise evaluation could be clarified clearly by getting the physical factors relevant to subjective diffuseness of noise field, interaural time delay for the horizontal angle and effective duration of the envelope of the normalized autocorrelation. Comparing with temporal factors, spatial factors such as interaural time delay for the horizontal angle and the physical factor relevant to subjective diffuseness of noise field derived from interaural cross-correlation function had more effects on subjective noise annoyance evaluation.