【语音识别】基于GUI DTW的0-9数字语音识别【Matlab 334期】

一、简介

1 DTW原理
动态时间规整DTW是一个典型的优化问题，它用满足一定条件的的时间规整函数W(n)描述测试模板和参考模板的时间对应关系，求解两模板匹配时累计距离最小所对应的规整函数。

假设我们有两个时间序列Q和C，他们的长度分别是n和m：（实际语音匹配运用中，一个序列为参考模板，一个序列为测试模板，序列中的每个点的值为语音序列中每一帧的特征值。例如语音序列Q共有n帧，第i帧的特征值（一个数或者一个向量）是qi。至于取什么特征，在这里不影响DTW的讨论。我们需要的是匹配这两个语音序列的相似性，以达到识别我们的测试语音是哪个词）

Q = q1, q2,…,qi,…, qn ;

C = c1, c2,…, cj,…, cm ;

如果n=m，那么就用不着折腾了，直接计算两个序列的距离就好了。但如果n不等于m我们就需要对齐。最简单的对齐方式就是线性缩放了。把短的序列线性放大到和长序列一样的长度再比较，或者把长的线性缩短到和短序列一样的长度再比较。但是这样的计算没有考虑到语音中各个段在不同情况下的持续时间会产生或长或短的变化，因此识别效果不可能最佳。因此更多的是采用动态规划（dynamic programming）的方法。

为了对齐这两个序列，我们需要构造一个n x m的矩阵网格，矩阵元素(i, j)表示qi和cj两个点的距离d(qi, cj)（也就是序列Q的每一个点和C的每一个点之间的相似度，距离越小则相似度越高。这里先不管顺序），一般采用欧式距离，d(qi, cj)= (qi-cj)2（也可以理解为失真度）。每一个矩阵元素(i, j)表示点qi和cj的对齐。DP算法可以归结为寻找一条通过此网格中若干格点的路径，路径通过的格点即为两个序列进行计算的对齐的点。
在这里插入图片描述

注明：先把模板序列和测试序列的每个点相对应的距离算出来，构成一个m xn的矩阵。然后根据每个元素的代价计算一条最短路径。这里的计算要符合以上三个约束。即，一个点的代价=这个点的值+来自min{下、左、斜下这三个方向的值}。下、左、斜下这三个方向的值可以依次递归求得，直到（1，1）点。
2 一般要求规整函数满足如下约束：
在这里插入图片描述

二、源代码

 function varargout = main(varargin)
% MAIN MATLAB code for main.fig
%      MAIN, by itself, creates a new MAIN or raises the existing
%      singleton*.
%
%      H = MAIN returns the handle to a new MAIN or the handle to
%      the existing singleton*.
%
%      MAIN('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in MAIN.M with the given input arguments.
%
%      MAIN('Property','Value',...) creates a new MAIN or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before main_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to main_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 main

% Last Modified by GUIDE v2.5 30-Mar-2016 14:29:41

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
                   'gui_Singleton',  gui_Singleton, ...
                   'gui_OpeningFcn', @main_OpeningFcn, ...
                   'gui_OutputFcn',  @main_OutputFcn, ...
                   'gui_LayoutFcn',  [] , ...
                   'gui_Callback',   []);
if nargin && ischar(varargin{
    
    1})
    gui_State.gui_Callback = str2func(varargin{
    
    1});
end

if nargout
    [varargout{
    
    1:nargout}] = gui_mainfcn(gui_State, varargin{
    
    :});
else
    gui_mainfcn(gui_State, varargin{
    
    :});
end
% End initialization code - DO NOT EDIT


% --- Executes just before main is made visible.
function main_OpeningFcn(hObject, eventdata, handles, varargin)
% This function has no output args, see OutputFcn.
% hObject    handle to figure
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
% varargin   command line arguments to main (see VARARGIN)

% Choose default command line output for main
handles.output = hObject;

% Update handles structure
guidata(hObject, handles);

% UIWAIT makes main wait for user response (see UIRESUME)
% uiwait(handles.figure1);


% --- Outputs from this function are returned to the command line.
function varargout = main_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 structure
varargout{
    
    1} = handles.output;



function edit1_Callback(hObject, eventdata, handles)
% hObject    handle to edit1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
file_path = get( hObject , 'String' ) ;
handles.file_path = file_path ;
guidata( hObject , handles ) ;

% Hints: get(hObject,'String') returns contents of edit1 as text
%        str2double(get(hObject,'String')) returns contents of edit1 as a double


% --- Executes during object creation, after setting all properties.
function edit1_CreateFcn(hObject, eventdata, handles)
% hObject    handle to edit1 (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 pushbutton1.
%%选择识别样本
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
global file1 pathname
[file1,pathname]=uigetfile('*.wav','请选择要识别的样本');%跳出对话框
fname=fullfile(pathname,file1);
[k,fs]=wavread(fname);
    sound(k,fs); %播放声音
set(handles.edit3,'string','识别结果'); 



% --- Executes on button press in pushbutton2.
%%开始训练按钮
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)
warning off
file_path = get( handles.edit1 , 'String' ) ;
T=0;
h = waitbar(0,'正在训练，请稍等...');
for i=0:9
    fname=fullfile(file_path,sprintf('%d0.wav',i));
    [k,fs]=wavread(fname);
    [StartPoint,EndPoint]=vad(k,fs);
    cc=mfcc(k);
    cc=cc(StartPoint-2:EndPoint-2,:);
    ref(i+1).StartPoint=StartPoint;
    ref(i+1).EndPoint=EndPoint;
    ref(i+1).mfcc=cc;
    waitbar( i/9 ) ;
end