王勇 孟华 陈正武 魏春华 刘垒

摘   要：直升机辐射的声信号在空气中衰减速度慢、传播距离远，是直升机目标识别的主要依据.受人类听觉系统优异的声音信号识别能力的启发，提出了基于人耳听觉感知特性的Gammatone倒谱系数（Gammatone Cepstral Coefficients，GTCC）特征提取方法用于直升机声信号的识别. 通过仿真实验，详细研究了参数设置对识别系统性能的影响，以及识别算法在噪声环境下的鲁棒性、对各种分类器的普遍适用性和相对其他特征提取方法的优越性，对实验结果给出了合理的解释. 实验结果表明，所提出的方法能够根据声信号有效地辨识直升机的类别，具有很好的抗噪声干扰能力，有一定的应用前景. 不同参数设置对识别性能的影响程度不同，其中窗函数长度、Gammatone倒谱系数特征数量和低频声信号对识别率的影响较大，而高频声信号对目标识别的影响较小.

关键词：声信号;识别;直升机;Gammatone滤波器;倒谱系数

中图分类号：TP391.4;V275.1            文献标志码：A

Recognition of Helicopter Acoustic Signal Based

on Gammatone Cepstral Coefficients

WANG Yong1?，MENG Hua2，CHEN Zhengwu1，WEI Chunhua1，LIU Lei1

（1. Key Laboratory of Aerodynamic Noise Control，China Aerodynamics Research

and Development Center，Mianyang 621000，China;

2. School of Mathematics，Southwest Jiaotong University，Chengdu 611756，China）

Abstract：The acoustic signal radiated by the helicopter has a slow attenuation speed and a long propagation distance in the air， which is the main basis for recognition of helicopter target. Inspired by the excellent sound signal recognition ability of the human auditory system， an auditory perceptual feature extraction method based on Gammatone cepstral coefficients（GTCC） is proposed to classify helicopter acoustic signal.  Through the simulation experiments，the influence of parameter settings on the recognition performance， the robustness of the proposed method in noisy environments， the universal applicability to various classifiers， and the superiority to other helicopter acoustic signal feature extraction methods were studied in detail. Reasonable explanations of the observed experimental results were also given in this paper. The results show that the proposed method can effectively identify the type of helicopter according to the acoustic signal， and has good anti-interference ability to noise， which has certain application prospects. It is also shown that different parameter settings have different effects on the recognition performance， where the length of window function， the number of Gammatone cepstral coefficient features and the low-frequency acoustic signal have a great influence on the recognition accuracy， while high-frequency acoustic signal has little influence on the recognition.

Key words：acoustic signal;recognition;helicopter;Gammatone filter;cepstral coefficient

直升機具有独特的高机动、低空或超低空飞行能力，不易被雷达、红外等探测识别手段发现. 但直升机辐射的噪声，特别是其旋翼产生的强中低频噪声，在空气中的衰减速率慢、传播距离远，极易被地面人员感知，也极易被专用的噪声预警系统探测和识别.

直升机声信号的识别与一般模式识别过程一样，通常包含特征提取和分类识别两个阶段. 特征提取的主要目的是通过变换或映射的方法，在大幅度降低数据维数的……