基于matlab的语音信号分析与处理

% 程序11.1：speechenhancement.m clear all; %-------------------------------读入语音文件------------------------------------------------------------ [speech,fs,nbits]=wavread('speech_clean1.wav'); %读入数据 %-------------------------------参数定义---------------------------------------------------------------- winsize=256; %窗长 n=0.04; %噪声水平 size=length(speech); %语音长度 numofwin=floor(size/winsize); %帧数 ham=hamming(winsize)'; %产生哈明窗 hamwin=zeros(1,size); %定义哈明窗的长度 enhanced=zeros(1,size); %定义增强语音的长度 x=speech'+ n*randn(1,size); %产生带噪信号 noisy=n*randn(1,winsize); %噪声估计 N = fft(noisy); %对噪声傅里叶变换 nmag= abs(N); %噪声功率谱 %-------------------------------分帧-------------------------------------------------------------------- for q=1:2*numofwin-1 frame=x(1+(q-1)*winsize/2:winsize+(q-1)*winsize/2); %对带噪语音帧间重叠一半取值 hamwin(1+(q-1)*winsize/2:winsize+(q-1)*winsize/2)=... hamwin(1+(q-1)*winsize/2:winsize+(q-1)*winsize/2)+ham; %加窗 y=fft(frame.*ham); %对带噪语音傅里叶变换 mag = abs(y); %带噪语音功率谱 phase = angle(y); %带噪语音相位 %-------------------------------幅度谱减------------------------------------------------------------------- for i=1:winsize if mag(i)-nmag(i)>0 clean(i)= mag(i)-nmag(i); else clean(i)=0; end end %---------------------------%在频域中重新合成语音------------------------------------------------- spectral= clean.*exp(j*phase); %------------------------反傅里叶变换并重叠相加--------------------------------------------------- enhanced(1+(q-1)*winsize/2:winsize+(q-1)*winsize/2)=... enhanced(1+(q-1)*winsize/2:winsize+(q-1)*winsize/2)+real(ifft(spectral)); end %---------------------------除去Hamming窗引起的增益----------------------------------------------- for i=1:size if hamwin(i)==0 enhanced(i)=0; else enhanced(i)=enhanced(i)/hamwin(i); end end %-----------------------计算增强前后信噪比-------------------------------------------------------- SNR1 = 10*log10(var(speech')/var(noisy)); %加噪语音信噪比 SNR2 = 10*log10(var(speech')/var(enhanced-speech')); %增强语音信噪比 wavwrite(x,fs,nbits,'noisy.wav'); %输出带噪信号 wavwrite(enhanced,fs,nbits,'enhanced.wav'); %输出增强语音 %-------------------------------画波形----------------------------------------------------------- figure(1); subplot(3,1,1);plot(speech'); title('原始语音波形'); xlabel('样点数');ylabel('幅度'); axis([0 2.5*10^4 -0.3 0.3]); subplot(3,1,2);plot(x); title('加噪语音波形'); xlabel('样点数');ylabel('幅度'); axis([0 2.5*10^4 -0.3 0.3]); subplot(3,1,3);plot(enhanced); title('增强语音波形'); xlabel('样点数');ylabel('幅度');axis([0 2.5*10^4 -0.3 0.3]);