基于传声器阵列的声源定位

文中对利用传声器进行语音声源定位时所面临的几个问题作了讨论。同时分析比较了类主要的源定位方法，并给出了基于可控波束形成的仿真结果。     

基于麦克风阵列的相容时延矢量声源定位方法

时延估计是常用的声源定位方法,传统的算法将定位分为两个步骤,即先估计麦克风阵列中每一对基元的接收信号时延,然后根据这些时延用几何的方法确定声源的位置。在低信噪比下,一对麦克风的时延估计误差较大,导致定位误差较大。相容时延矢量估计算法将两步合为一步,没有逐对估计时延,而是构造一个目标函数,通过搜索得到声源的位置。仿真结果表明,在低信噪比下,只需要较短的数据,该算法仍可得到较高的定位精度。     

基于遗传算法的声源三维定位方法

相位变换加权的可控响应功率（SRP-PHAT）算法是一种基于麦克风阵列的鲁棒声源定位方法,该算法在有混响和噪声的环境下仍有较高的定位精度.但该算法用网格法对整个声源空间进行搜索,逐点计算其目标函数,因而总的计算量非常大,不适用于实时定位系统.针对SRP-PHAT的特点,采用遗传算法进行搜索,使总的计算量大幅度降低.仿真结果表明在混响时间为300ms,信噪比为5dB的条件下,该算法仍可达到较高的定位精度.     

TDOA中几种时延估计算法的比较

在现有的传声器阵列声源定位方法中,基于声达时间差(TDOA)估计定位法计算量较小,定位精度较高,同时也易于实现实时系统,是目前声源定位法中常用的方法。采用该方法最重要的就是进行时间延迟估计(TDE),其精确性直接影响到定位的准确与否。概括了基于传声器阵列的声达时间差(TDOA)估计定位法中几种时间延迟估计的算法,给出了部分算法的仿真结果,分析了每种算法中存在的优缺点并同时指出了需进一步研究的问题。     

A weighted feature reduction method for power spectra of radar HRRPs

Feature reduction is a key process in pattern recognition. This paper deals with the feature reduction methods for a time-shift invariant feature, power spectrum, in Radar Automatic Target Recognition （RATR） using High-Resolution Range Profiles （HRRPs）. Several existing feature reduction methods in pattern recognition are analyzed, and a weighted feature reduction method based on Fisher＇s Discriminant Ratio （FDR） is proposed in this paper. According to the characteristics of radar HRRP target recognition, this proposed method searches the optimal weight vector for power spectra of HRRPs by means of an iterative algorithm, and thus reduces feature dimensionality. Compared with the method of using raw power spectra and some existing feature reduction methods, the weighted feature reduction method can not only reduce feature dimen- sionality, but also improve recognition performance with low computation complexity. In the recognition experiments based on measured data, the proposed method is robust to different test data and achieves good recognition results.