语音信号处理实验

哈尔滨工程大学实验报告班级：电信三班学号：***********名：***语音信号处理实验一、实验目的1、掌握短时能量的求解方法、短时平均过零率的求解方法，对输入的语音信号进行端点检测。

2、掌握语音信号的Mel 倒谱特征（MFCC ）的求解方法，语音信号的线性预测原理以及LPC 特征的求解方法。

3、掌握语音信号基频的概念，加深对基频刻画声调特征作用的理解，掌握语音信号基频特征的典型求解方法。

4、掌握MATLAB 相应的功能以及使用方法。

二、仪器设备HP 计算机、MATLAB 软件 三、实验原理（一）语音信号的短时分析端点检测是语音信号处理过程中非常重要的一步，它的准确性直接影响到语音信号处理的速度和结果。

本次实验利用短时过零率和短时能量相结合的语音端点检测算法利用短时过零率来检测清音，用短时能量来检测浊音，两者相配合便实现了信号信噪比较大情况下的端点检测。

先引入以下三个概念 1、短时能量计算定义n 时刻某语言信号的短时平均能量En 为：∑∑--=+∞∞--=-=nN n m m n w m x m n w m x En )1(22)]()([)]()([式中N 为窗长，可见短时平均能量为一帧样点值的平方和。

特殊地，当窗函数为矩形窗时，有∑--==nN n m m x En )1(2)(2、短时过零率过零就是指信号通过零值。

过零率就是每秒内信号值通过零值的次数。

对于离散时间序列，过零则是指序列取样值改变符号，过零率则是每个样本的改变符号的次数。

对于语音信号，则是指在一帧语音中语音信号波形穿过横轴（零电平）的次数。

可以用相邻两个取样改变符号的次数来计算。

如果窗的起点是n=0，短时过零率Z 为 波形穿过横轴（零电平）的次数|))1(())((|2110∑-=--=N n w w n S Sgn n S Sgn Z{00,1,1)sgn(≥<-=x x x短时过零可以看作信号频率的简单度量浊音的短时平均幅度最大，无声的短时平均幅度最小，清音的短时过零率最大，无声居中，浊音的短时过零率最小。

3、短时自相关函数∑--=+=1)()()(k N n www k n s n s k R①是偶函数；②s(n)是周期的，那么R （k ）也是周期的； ③可用于基音周期估计和线性预测分析4、判断语音信号的起点和终点利用过零率检测清音，用短时能量检测浊音，两者配合。

首先为短时能量和过零率分别确定两个门限，一个是较低的门限数值较小，对信号的变化比较敏感，很容易超过；另一个是比较高的门限，数值较大。

低门限被超过未必是语音的开始，有可能是很短的噪声引起的，高门限被超过并且接下来的自定义时间段内的语音超过低门限，意味着信号开始。

此时整个端点检测可分为四段：静音段、过渡段、语音段、结束。

实验时使用一个变量表示当前状态。

静音段，如果能量或过零率超过低门限，就开始标记起始点，进入过渡段。

过渡段当两个参数值都回落到低门限以下，就将当前状态恢复到静音状态。

而如果过渡段中两个参数中的任一个超过高门限，即被认为进入语音段。

处于语音段时，如果两参数降低到门限以下，而且总的计时长度小于最短时间门限，则认为是一段噪音，继续扫描以后的语音数据，否则标一记结束端点。

（二）语音信号的特征提取由于频率响应)(jwe H 反映声道的频率响应和被分析信号的谱包络，因此用|)(|log jw e H 做反傅里叶变换求出的LPC 倒谱系数。

通过线性预测分析得到的合成滤波器的系统函数为)1/(1)(1∑=--=pi ii z a z H ，其冲激响应为h(n)。

h(n)的倒谱为)(^n h ，∑+∞=-=1^^)()(n nzn h z H 就是说)(^z H 的逆变换)(^n h 是存在的。

设0)0(^=h ，将式∑+∞=-=1^^)()(n nz n h z H 两边同时对1-z 求导，得∑∑+∞=--=--∂∂=-∂∂1^1111)(]11log[n npi i z n h z za z 得到∑∑∑∞+==-=+-+--=11111^1)(n p i ii pi i in z a zia z n h n ，于是有∑∑∑+∞=+∞=+-+-=-=-1111^11)()1(n n i i n pi i z ia zn h n z a 令其左右两边z 的各次幂前系数分别相等，得到)(^n h 和i a 间的递推关系⎪⎪⎪⎩⎪⎪⎪⎨⎧>--=≤≤--+==∑∑=-=p i i n i i n p n n h a n i n h pn k n h a n i a n h a h 1^^11^^1^),1()1()(1),()1()()1( ，按其可直接从预测系数｛i a ｝求得倒谱)(^n h 。

这个倒谱是根据线性预测模型得到的，又称为LPC 倒谱。

LPC 倒谱由于利用线性预测中声道系统函数H （z ）的最小相位特性，因此避免了一般同态处理中求复对数的麻烦。

（三）语音信号的基频提取浊音信号的自相关函数在基因周期的整数倍位置上出现峰值，而清音的自相关函数没有明显的峰值出现。

因此检测自相关函数是否有峰值就可以判断是清音还是浊音，而峰-峰值之间对应的就是基音周期。

影响从自相关函数中正确提取基音周期的最主要原因是声道响应。

当基音的周期性和共振峰的周期性混在一起时，被检测出来的峰值可能会偏离原来峰值的真实位置。

另外，在某些浊音中，第一共振频率可能会等于或低于基音频率。

此时，如果其幅度很高，它就可能在自相关函数中产生一个峰值，而该峰值又可以同基音频率的峰值相比拟。

1、自相关函数对于离散的语音信号x(n)，它的自相关函数定义为：R(k)=Σx(n)x(n-k)，如果信号x(n))具有周期性，那么它的自相关函数也具有周期性，而且周期与信号x(n) 的周期性相同。

自相关函数提供了一种获取周期信号周期的方法。

在周期信号周期的整数倍上，它的自相关函数可以达到最大值，因此可以不考虑起始时间，而从自相关函数的第一个最大值的位置估计出信号的基音周期，这使自相关函数成为信号基音周期估计的一种工具。

2、短时自相关函数语音信号是非平稳的信号，所以对信号的处理都使用短时自相关函数。

短时自相关函数是在信号的第N个样本点附近用短时窗截取一段信号，做自相关计算所得的结果Rm(k)=Σx(n)x(n-k)式中，n表示窗函数是从第n点开始加入。

3、算法通过对自相关基音检测原理的分析,考虑到检测准确度和检测速率2方面的因素,提出了算法实现方案,并对算法进行了MATLAB编程实现。

四、实验内容利用MA TLAB画出信号分析界面，实现语音信号文件的提取，分析并画图，再进行LPC 和MFCC分析，并画图，经过相应的计算和分析，最终能够识别男或女的声音。

画出的界面如下图所示:程序文本:function varargout = voice(varargin)% VOICE MATLAB code for voice.fig% VOICE, by itself, creates a new VOICE or raises the existing% singleton*.%% H = VOICE returns the handle to a new VOICE or the handle to% the existing singleton*.%% VOICE('CALLBACK',hObject,eventData,handles,...) calls the local% function named CALLBACK in VOICE.M with the given input arguments. %% VOICE('Property','Value',...) creates a new VOICE or raises the % existing singleton*. Starting from the left, property value pairs are% applied to the GUI before voice_OpeningFcn gets called. An% unrecognized property name or invalid value makes property application% stop. All inputs are passed to voice_OpeningFcn via varargin.%% *See GUI Options on GUIDE's Tools menu. Choose "GUI allows only one% instance to run (singleton)".%% See also: GUIDE, GUIDATA, GUIHANDLES% Edit the above text to modify the response to help voice% Last Modified by GUIDE v2.5 22-Apr-2017 19:01:57% Begin initialization code - DO NOT EDITgui_Singleton = 1;gui_State = struct('gui_Name', mfilename, ...'gui_Singleton', gui_Singleton, ...'gui_OpeningFcn', @voice_OpeningFcn, ...'gui_OutputFcn', @voice_OutputFcn, ...'gui_LayoutFcn', [] , ...'gui_Callback', []);if nargin && ischar(varargin{1})gui_State.gui_Callback = str2func(varargin{1});endif nargout[varargout{1:nargout}] = gui_mainfcn(gui_State, varargin{:});elsegui_mainfcn(gui_State, varargin{:});end% End initialization code - DO NOT EDIT% --- Executes just before voice is made visible.function voice_OpeningFcn(hObject, eventdata, handles, varargin)% This function has no output args, see OutputFcn.% hObject handle to figure% handles structure with handles and user data (see GUIDATA)% varargin command line arguments to voice (see VARARGIN)% Choose default command line output for voicehandles.output = hObject;% Update handles structureguidata(hObject, handles);% UIWAIT makes voice wait for user response (see UIRESUME)% uiwait(handles.figure1);set(handles.read_path,'String','myspeech.wav');addpath('F:\voicebox');% --- Outputs from this function are returned to the command line. function varargout = voice_OutputFcn(hObject, eventdata, handles) % varargout cell array for returning output args (see VARARGOUT); % hObject handle to figure% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA)% Get default command line output from handles structurevarargout{1} = handles.output;% --- Executes on button press in LPC.function LPC_Callback(hObject, eventdata, handles)% hObject handle to LPC (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA)% Hint: get(hObject,'Value') returns toggle state of LPC% --- Executes on button press in MFCC.function MFCC_Callback(hObject, eventdata, handles)% hObject handle to MFCC (see GCBO)% handles structure with handles and user data (see GUIDATA)% Hint: get(hObject,'Value') returns toggle state of MFCC% --- Executes on button press in pushbutton2.function pushbutton2_Callback(hObject, eventdata, handles)% hObject handle to pushbutton2 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)function read_path_Callback(hObject, eventdata, handles)% hObject handle to read_path (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of read_path as text% str2double(get(hObject,'String')) returns contents of read_path as a double% --- Executes during object creation, after setting all properties. function read_path_CreateFcn(hObject, eventdata, handles)% hObject handle to read_path (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.if ispc && isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');end% --- Executes on button press in pushbutton3.function pushbutton3_Callback(hObject, eventdata, handles)% hObject handle to pushbutton3 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)channel=1;temp=wavread(get(handles.read_path,'string'));y=temp(:,channel);plot(y);% --- Executes on button press in pushbutton4.function pushbutton4_Callback(hObject, eventdata, handles)% hObject handle to pushbutton4 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) channel=1;temp=wavread(get(handles.read_path,'string'));y=temp(:,channel);f=enframe(y,200,200);y=f(150,:);plot(handles.top, y);% --- Executes on button press in LPCplot1.function LPCplot1_Callback(hObject, eventdata, handles)% hObject handle to LPCplot1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA)if get(handles.LPC,'Value')==1channel=1;temp=wavread(get(handles.read_path,'string'));speech=temp(:,channel);f_temp=enframe(speech,200,200);d_temp=f_temp(25,:);plot(handles.top,d_temp);p=12;ar=lpcauto(d_temp,p);Y=lpcar2ff(ar,255);est_x=filter([0-ar(2:end)],1,d_temp);plot(handles.kk,est_x);end% --- Executes on button press in zuocha.function zuocha_Callback(hObject, eventdata, handles)% hObject handle to zuocha (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA)if get(handles.LPC,'Value')==1channel=1;temp=wavread(get(handles.read_path,'string'));speech=temp(:,channel);f_temp=enframe(speech,200,200);d_temp=f_temp(25,:);p=12;ar=lpcauto(d_temp,p);Y=lpcar2ff(ar,255);est_x=filter([0-ar(2:end)],1,d_temp)-d_temp;plot(handles.qq,est_x);end% --- Executes on button press in MFCCplot.function MFCCplot_Callback(hObject, eventdata, handles)% hObject handle to MFCCplot (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA)if get(handles.MFCC,'Value')==1channel=1;temp= wavread(get(handles.read_path,'string'));y=temp(:,channel);fs=8000;c=melcepst(y,fs);n = str2double(get(handles.mfcc_num, 'string'));c = c(:,n);plot(handles.kk,c);end% --- Executes on button press in read.function read_Callback(hObject, eventdata, handles)% hObject handle to read (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB % handles structure with handles and user data (see GUIDATA) signal = wavread(get(handles.read_path,'string'));plot(handles.top, signal);function mfcc_num_Callback(hObject, eventdata, handles)% hObject handle to mfcc_num (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of mfcc_num as text% str2double(get(hObject,'String')) returns contents of mfcc_num as a double% --- Executes during object creation, after setting all properties. function mfcc_num_CreateFcn(hObject, eventdata, handles)% hObject handle to mfcc_num (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.if ispc && isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');endfunction kmeans_num_Callback(hObject, eventdata, handles)% hObject handle to kmeans_num (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of kmeans_num as text % str2double(get(hObject,'String')) returns contents ofkmeans_num as a double% --- Executes during object creation, after setting all properties. function kmeans_num_CreateFcn(hObject, eventdata, handles)% hObject handle to kmeans_num (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.if ispc && isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');end% --- Executes on button press in keans.function keans_Callback(hObject, eventdata, handles)% hObject handle to keans (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)channel = 1; %声道选择temp = wavread(get(handles.read_path,'String')); %读入语音信号speech = temp(:,channel); %量化语音信号fs = 8000; %选择采样频率c = melcepst(speech, fs); %梅尔系数的采集,，默认12位n = str2double(get(handles.kmeans_num,'String'));[idx ,C] = kmeans(c,n);stem(handles.qq, idx);function result_Callback(hObject, eventdata, handles)% hObject handle to result (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hints: get(hObject,'String') returns contents of result as text% str2double(get(hObject,'String')) returns contents of result as a double% --- Executes during object creation, after setting all properties. function result_CreateFcn(hObject, eventdata, handles)% hObject handle to result (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles empty - handles not created until after all CreateFcns called% Hint: edit controls usually have a white background on Windows.% See ISPC and COMPUTER.if ispc && isequal(get(hObject,'BackgroundColor'),get(0,'defaultUicontrolBackgroundColor'))set(hObject,'BackgroundColor','white');end% --- Executes on button press in male.function male_Callback(hObject, eventdata, handles)% hObject handle to male (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hint: get(hObject,'Value') returns toggle state of male% --- Executes on button press in female.function female_Callback(hObject, eventdata, handles)% hObject handle to female (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% Hint: get(hObject,'Value') returns toggle state of female% --- Executes on button press in GMM.function GMM_Callback(hObject, eventdata, handles)% hObject handle to GMM (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)[xx,fs] = wavread(get(handles.read_path,'String')); %读入语音信号x=xx/max(abs(xx)); % 幅度归一化N=length(xx); % 取信号长度time=(0:N-1)/fs; % 计算时间刻度wlen=200; inc=100;y=enframe(x,wlen,inc)'; % 分帧etemp=sum(y.^2); % 求取短时平均能量etemp=etemp/max(etemp); % 能量幅值归一化fn=size(y,2); % 帧数T1=0.002; % 设置阈值T2=0.01;[voiceseg,vsl,SF,NF]=vad_param1D(etemp,T1,T2);% 用一个参数端点检测signal = x((voiceseg(1).begin*inc):(voiceseg(1).end*inc));%提取语音信号c = melcepst(signal, fs); %梅尔系数[idx ,C] = kmeans(c,1); %聚类及聚类中心load('D:\test\GMM1.mat')load('D:\test\GMM2.mat')[flp(1), rp0, kh0, kp0] = gaussmixp(C, fm0,fv0,fw0);[flp(2), rp0, kh0, kp0] = gaussmixp(C, fm1,fv1,fw1);[flp(3), rp0, kh0, kp0] = gaussmixp(C, fm2,fv2,fw2);[flp(4), rp0, kh0, kp0] = gaussmixp(C, fm3,fv3,fw3); [flp(5), rp0, kh0, kp0] = gaussmixp(C, fm4,fv4,fw4); [flp(6), rp0, kh0, kp0] = gaussmixp(C, fm5,fv5,fw5); [flp(7), rp0, kh0, kp0] = gaussmixp(C, fm6,fv6,fw6); [flp(8), rp0, kh0, kp0] = gaussmixp(C, fm7,fv7,fw7); [flp(9), rp0, kh0, kp0] = gaussmixp(C, fm8,fv8,fw8); [flp(10), rp0, kh0, kp0] = gaussmixp(C, fm9,fv9,fw9); [lp(1), rp0, kh0, kp0] = gaussmixp(C, m0,v0,w0);[lp(2), rp0, kh0, kp0] = gaussmixp(C, m1,v1,w1);[lp(3), rp0, kh0, kp0] = gaussmixp(C, m2,v2,w2);[lp(4), rp0, kh0, kp0] = gaussmixp(C, m3,v3,w3);[lp(5), rp0, kh0, kp0] = gaussmixp(C, m4,v4,w4);[lp(6), rp0, kh0, kp0] = gaussmixp(C, m5,v5,w5);[lp(7), rp0, kh0, kp0] = gaussmixp(C, m6,v6,w6);[lp(8), rp0, kh0, kp0] = gaussmixp(C, m7,v7,w7);[lp(9), rp0, kh0, kp0] = gaussmixp(C, m8,v8,w8);[lp(10), rp0, kh0, kp0] = gaussmixp(C, m9,v9,w9);[x1,y1] = max(flp);[x2,y2] = max(lp);if x1>x2y = y1 - 1set(handles.male,'value',0);set(handles.female,'value',1);elsey = y2 - 1set(handles.male,'value',1);set(handles.female,'value',0);endset(handles.result,'String',y);五、实验结果1、LPC分析2、MFCC分析3、聚类4、判断六、实验总结与体会通过这次实验，对MATLAB的相应功能和使用方法有了更深的理解和体会，同时加深了课堂上所讲的MFCC和LPC的知识的理解。