说话人声纹身份认证技术中的关键是特征参数的准确性和模式识别的速率.为此,对识别对象的性别予以区分,并进行参数可自适应调整的Mel滤波器组设计,即通过Quartus II平台在Altera的DE2系列型号为EP2C35F672C6的开发板上完成高效率说话人声纹特征提取的SOC(片上系统)设计.设计具体步骤如下:首先,设计截止频率为400 Hz和200 Hz的低通滤波器以完成男女生基音频率的检测;然后,依据计算出的每一帧语音频谱的频率范围确定Mel滤波器组的最高频率并完成参数设计;最后,在Quartus II平台上完成Verilog-HDL代码设计,并封装为IP核完成SOC设计以及编译、仿真和下载验证.结果表明,Mel滤波器组利用率的提高有利于提高特征参数的准确性和识别速度.
The accuracy of characteristic parameter and pattern recognition rate among speaker voiceprint au- thentication technologies are important. In this paper, adaptive Mel filter banks are designed after the recogni- tion of the gender, and the SOC (system-on-chip)design of high efficiency speaker voiceprint feature extrac- tion is completed on the EP2C35F672C6 development board of Alterag DE2 series. First of all, two low-pass filters cutoff frequency of 200 Hz and 400 Hz are designed to complete the pitch frequency detection of male and female students. Then, the parameters of Mel filter banks are calculated by the highest frequency deduced from the frequency range of speech spectrum. Then, Verilog-HDL code encapsulated as IP core for SOC de- sign, compilation, simulation, and download authentication are finished on the Quartus II platform. The re- sults show that adaptive Mel filter banks can improve both the accuracy of characteristic parameters and the speed of recognition.