改进的梅尔倒谱系数在低空飞行器特征提取中的应用*

梅尔倒谱系数特征提取技术依据人耳的感知特性将声信号从线性频域转换到梅尔域,在语音识别中得到广泛应用。该文将梅尔倒谱系数技术用于小型低空飞行器的声信号特征提取中,并针对螺旋桨驱动类的小型低空飞行器具有稳定的强谐波特性,对梅尔倒谱系数特征提取中使用的梅尔滤波器进行改进,通过对此类谐波处的线性频谱与梅尔谱转换曲线的斜率进行投影替换,提高滤波器对该谐波处信号的感知敏感度。仿真结果表明,使用改进的梅尔倒谱系数特征提取方法对小型低空飞行器进行特征提取时,能够得到更低的等误识率,并且在低信噪比环境中,改进的梅尔倒谱系数特征提取方法具有更好的抗噪能力。

The application of improved Mel-frequency cepstral coefficients technology in the feature extraction of low-altitude aircraft

The MFCC feature extraction technology transforms the acoustic signal from the linear frequency domain to the Mel-domain based on the perceptive characteristics of human ear and is widely used in speech recognition. In this paper, MFCC technology is used to extract the acoustic signal features of small low-altitude aircraft, and force on the feature which steady-state strong harmonic of small low-altitude aircraft with propeller driven, to improve the Mel filter for MFCC feature extraction. Through the projection and replacement of the slope of the linear spectrum - Mel spectrum conversion curve of this kind of harmonics, improving the sensitivity of the filter to the signal of the harmonic. Simulation results show that using the improved MFCC method can get higher recognition rate, and in the low SNR environment, improved MFCC feature extraction method has better ability to resist noise.