一、案例简介
主要介绍的是的语音信号的简单处理。本论文针对以上问题，运用数字信号学基本原理实现语音信号的处理，在matlab7.0环境下综合运用信号提取，幅频变换以及傅里叶变换、滤波等技术来进行语音信号处理。我所做的工作就是在matlab2014a软件上编写一个处理语音信号的程序，能对语音信号进行采集，并对其进行各种处理，达到简单语音信号处理的目的。
对语音信号的研究，本论文采用了设计滤波器的基本研究方法来达到研究语音信号去噪的目的，最终结合图像以及对语音信号的回放，通过对比，得出结论。
本课题的研究基本步骤如下：
1、语音信号的录制。
2、在MATLAB平台上读入语音信号。
3、绘制频谱图并回放原始语音信号。
4、利用MATLAB编程加入一段正弦波噪音，设计滤波器去噪。
5、利用MATLAB编程加入一段随机噪音信号，设计滤波器去噪，并分别绘制频谱图、回放语音信号。
二、部分源代码
function varargout = GUI_FILTER(varargin)
% GUI_FILTER M-file for GUI_FILTER.fig
% GUI_FILTER, by itself, creates a new GUI_FILTER or raises the existing
% singleton*.
%
% H = GUI_FILTER returns the handle to a new GUI_FILTER or the handle to
% the existing singleton*.
%
% GUI_FILTER('CALLBACK',hObject,eventData,handles,...) calls the local
% function named CALLBACK in GUI_FILTER.M with the given input arguments.
%
% GUI_FILTER('Property','Value',...) creates a new GUI_FILTER or raises the
% existing singleton*. Starting from the left, property value pairs are
% applied to the GUI before GUI_FILTER_OpeningFunction gets called. An
% unrecognized property name or invalid value makes property application
% stop. All inputs are passed to GUI_FILTER_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 GUI_FILTER
% Last Modified by GUIDE v2.5 26-Mar-2021 14:56:44
% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name', mfilename, ...
'gui_Singleton', gui_Singleton, ...
'gui_OpeningFcn', @GUI_FILTER_OpeningFcn, ...
'gui_OutputFcn', @GUI_FILTER_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 GUI_FILTER is made visible.
function GUI_FILTER_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 GUI_FILTER (see VARARGIN)
% Choose default command line output for GUI_FILTER
set(handles.textStatic1,'String','Low Freq (HZ):');
set(handles.textStatic2,'Visible','Off');
set(handles.editF2,'Visible','Off');
handles.SelectedFilter = 1;
set(handles.sliderSNR,'Min',-35);
set(handles.sliderSNR,'Max', 15);
handles.SNR = (get(handles.sliderSNR,'Value'));
set(handles.editSNR, 'String', [num2str(handles.SNR) ' dB SNR'] );
handles.fileLoaded = 0;
handles.fileNoisy = 0;
handles.fileFinal = 0;
handles.output = hObject;
% Update handles structure
guidata(hObject, handles);
% UIWAIT makes GUI_FILTER wait for user response (see UIRESUME)
% uiwait(handles.figure1);
% --- Outputs from this function are returned to the command line.
function varargout = GUI_FILTER_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;
% --- Executes on button press in buttonLoad.
function buttonLoad_Callback(hObject, eventdata, handles)
% hObject handle to buttonLoad (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
[FileName,PathName] = uigetfile({'*.wav'},'Load Wav File');
[x,Fs] = wavread([PathName '/' FileName]);
handles.x = x ./ max(abs(x));
handles.Fs = Fs;
axes(handles.axesSignal1);
time = 0:1/Fs:(length(handles.x)-1)/Fs;
plot(time, handles.x);
axis([0 max(time) -1 1]);
axes(handles.axesSpec1);
specgram(handles.x, 1024, handles.Fs);
title('Signal Spectrogram');
handles.fileLoaded = 1;
axes(handles.axesSpecNoise); cla;
axes(handles.axesSpec2); cla;
axes(handles.axesSpecFinal); cla;
handles.fileNoisy = 0;
handles.fileFinal = 0;
guidata(hObject, handles);
% --- Executes on button press in buttonPlay.
function buttonPlay_Callback(hObject, eventdata, handles)
% hObject handle to buttonPlay (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
if (handles.fileLoaded==1)
sound(handles.x, handles.Fs);
end
% --- Executes on selection change in popupmenu1.
function popupmenu1_Callback(hObject, eventdata, handles)
% hObject handle to popupmenu1 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% Hints: contents = get(hObject,'String') returns popupmenu1 contents as cell array
% contents{get(hObject,'Value')} returns selected item from popupmenu1
S = get(hObject,'Value');
switch (S)
case (1)
set(handles.textStatic1,'String','Low Freq (HZ):');
set(handles.textStatic2,'Visible','Off');
set(handles.editF2,'Visible','Off');
handles.SelectedFilter = 1;
case (2)
set(handles.textStatic1,'String','High Freq (HZ):');
set(handles.textStatic2,'Visible','Off');
set(handles.editF2,'Visible','Off');
handles.SelectedFilter = 2;
case (3)
set(handles.textStatic1,'String','Low Freq (HZ):');
set(handles.textStatic2,'Visible','On');
set(handles.editF2,'Visible','On');
set(handles.textStatic2,'String','High Freq (HZ):');
handles.SelectedFilter = 3;
end
guidata(hObject, handles);
% --- Executes during object creation, after setting all properties.
function popupmenu1_CreateFcn(hObject, eventdata, handles)
% hObject handle to popupmenu1 (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles empty - handles not created until after all CreateFcns called
% Hint: popupmenu controls usually have a white background on Windows.
% See ISPC and COMPUTER.
if ispc
set(hObject,'BackgroundColor','white');
else
set(hObject,'BackgroundColor',get(0,'defaultUicontrolBackgroundColor'));
end
function editF1_Callback(hObject, eventdata, handles)
% hObject handle to editF1 (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 editF1 as text
% str2double(get(hObject,'String')) returns contents of editF1 as a double
% --- Executes during object creation, after setting all properties.
function editF1_CreateFcn(hObject, eventdata, handles)
% hObject handle to editF1 (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
set(hObject,'BackgroundColor','white');
else
set(hObject,'BackgroundColor',get(0,'defaultUicontrolBackgroundColor'));
end
function editF2_Callback(hObject, eventdata, handles)
% hObject handle to editF2 (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 editF2 as text
% str2double(get(hObject,'String')) returns contents of editF2 as a double
% --- Executes during object creation, after setting all properties.
function editF2_CreateFcn(hObject, eventdata, handles)
% hObject handle to editF2 (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
set(hObject,'BackgroundColor','white');
else
set(hObject,'BackgroundColor',get(0,'defaultUicontrolBackgroundColor'));
end
三、运行结果
四、matlab版本及参考文献
1 matlab版本
2014a
2 参考文献
[1]韩纪庆,张磊,郑铁然.语音信号处理（第3版）[M].清华大学出版社，2019.
[2]柳若边.深度学习:语音识别技术实践[M].清华大学出版社，2019.