【滤波器】基于FIR+IIR滤波器实现音频信号去噪含Matlab源码

1 简介

针对传统的滤波器设计方法效率低,方法复杂,不能满足高效高精度的需要等缺点,基于 MATLAB 研究了分别使用窗函数法和双线性变换法的 FIR 和 IIR 滤波器.将加入噪声的信号分别通过两种滤波器,滤除加入的噪声,对滤波前后的信号进行对比分析.通过仿真实验表明, FIR 滤波器与 IIR 的 Butterworth 滤波器都能很好地克服传统滤波器的不足,通过语谱图直观地对比发现基于窗函数法设计 FIR 滤波器比双线性法设计的 Butterworth 滤波器能更好地达到预定的去噪效果.

2 部分代码

function varargout = filter_2(varargin)
% FILTER_2 MATLAB code for filter_2.fig
% FILTER_2, by itself, creates a new FILTER_2 or raises the existing
% singleton*.
%
% H = FILTER_2 returns the handle to a new FILTER_2 or the handle to
% the existing singleton*.
%
% FILTER_2('CALLBACK',hObject,eventData,handles,...) calls the local
% function named CALLBACK in FILTER_2.M with the given input arguments.
%
% FILTER_2('Property','Value',...) creates a new FILTER_2 or raises the
% existing singleton*. Starting from the left, property value pairs are
% applied to the GUI before filter_2_OpeningFcn gets called. An
% unrecognized property name or invalid value makes property application
% stop. All inputs are passed to filter_2_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 filter_2
% Last Modified by GUIDE v2.5 16-May-2013 12:02:23
% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name', mfilename, ...
'gui_Singleton', gui_Singleton, ...
'gui_OpeningFcn', @filter_2_OpeningFcn, ...
'gui_OutputFcn', @filter_2_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 filter_2 is made visible.
function filter_2_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 filter_2 (see VARARGIN)
global response;
global analog;
global window1;
global digital;
global analog_choose;
response=1;
analog=1;
analog_choose=1;
window1=1;
digital=1;
%set(handles.function_value,'String','Butterworth');
%set(handles.method_value,'String','direct form');
set(handles.order,'Enable','off');
% Choose default command line output for filter_2
handles.output = hObject;
% Update handles structure
guidata(hObject, handles);
% UIWAIT makes filter_2 wait for user response (see UIRESUME)
% uiwait(handles.figure1);
% --- Outputs from this function are returned to the command line.
function varargout = filter_2_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 IIR_button.
function IIR_button_Callback(hObject, eventdata, handles)
% hObject handle to IIR_button (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
global analog_choose;
global response;
global analog;
if(get(hObject,'Value')==1) %当选中IIR时屏蔽FIR模块
set(handles.order_information,'String','order');
set(handles.FIR_button,'Value',0);
set(handles.filter_information,'String','IIR');
set(handles.window_function,'Enable','off');
set(handles.order,'Enable','off');
set(handles.view_window,'Enable','off');
set(handles.analog_filter,'Enable','on');
set(handles.Apass,'Enable','on');
set(handles.Astop,'Enable','on');
set(handles.order,'Enable','off');
set(handles.specify_order,'Enable','on'); set(handles.specify_order,'Value',0);%对阶数的处理
set(handles.custom_order,'Enable','on');set(handles.custom_order,'String','');
set(handles.min_order,'Enable','on');set(handles.min_order,'Value',0);
%get(handles.analog_method,'Value');
if( analog_choose==1)
set(handles.method_value,'String','direct form');
else
set(handles.method_value,'String','bilinear');
end
switch(analog)
case 1
set(handles.function_value,'String','Butterworth');
case 2
set(handles.function_value,'String','chebyshev1');
case 3
set(handles.function_value,'String','chebyshev2');
end
switch(response)
case 1
set(handles.type_information,'String','Lowpass');
case 2
set(handles.type_information,'String','Highpass');
case 3
set(handles.type_information,'String','Bandpass');
case 4
set(handles.type_information,'String','Bandstop');
end
else
set(handles.window_function,'Enable','on');
set(handles.order,'Enable','on');
set(handles.view_window,'Enable','on');
set(handles.order,'Enable','on');
end
% Hint: get(hObject,'Value') returns toggle state of IIR_button
% --- Executes on button press in FIR_button.
function FIR_button_Callback(hObject, eventdata, handles)
% hObject handle to FIR_button (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
global digital;
global response;
global window1;
if(get(hObject,'Value')==1) %当选中FIR时屏蔽IIR模块
set(handles.IIR_button,'Value',0);
set(handles.filter_information,'String','FIR');
set(handles.window_function,'Enable','on');
% set(handles.order,'Enable','on');
set(handles.view_window,'Enable','on');
set(handles.analog_filter,'Enable','off');
set(handles.Apass,'Enable','off');
set(handles.Astop,'Enable','off');
%set(handles.order,'Enable','on');
if(digital==2)%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%处理阶数
set(handles.specify_order,'Enable','off');
set(handles.custom_order,'Enable','off');
set(handles.min_order,'Enable','off');
set(handles.window_function,'Enable','off');
set(handles.view_window,'Enable','off');
set(handles.order_information,'String','sample')
set(handles.order,'Enable','on');
end
switch(response)
case 1
set(handles.type_information,'String','Lowpass');
case 2
set(handles.type_information,'String','Highpass');
case 3
set(handles.type_information,'String','Bandpass');
case 4
set(handles.type_information,'String','Bandstop');
end
if(digital==1)
set(handles.method_value,'String','window');
else
set(handles.method_value,'String','FSI');
end
switch(window1)
case 1
set(handles.function_value,'String','Hamming');
case 2
set(handles.function_value,'String','Blackman');
case 3
set(handles.function_value,'String','Hann');
case 4
set(handles.function_value,'String','Rectangular');
end
else
set(handles.analog_filter,'Enable','on');
set(handles.Apass,'Enable','on');
set(handles.Astop,'Enable','on');
set(handles.order,'Enable','off');
end
% Hint: get(hObject,'Value') returns toggle state of FIR_button
% --- If Enable == 'on', executes on mouse press in 5 pixel border.
% --- Otherwise, executes on mouse press in 5 pixel border or over filter_information.
function filter_information_ButtonDownFcn(hObject, eventdata, handles)
% hObject handle to filter_information (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
function Fs_edit_Callback(hObject, eventdata, handles)
% hObject handle to Fs_edit (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 Fs_edit as text
% str2double(get(hObject,'String')) returns contents of Fs_edit as a double
% --- Executes during object creation, after setting all properties.
function Fs_edit_CreateFcn(hObject, eventdata, handles)
% hObject handle to Fs_edit (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
function Fstop1_edit_Callback(hObject, eventdata, handles)
% hObject handle to Fstop1_edit (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 Fstop1_edit as text
% str2double(get(hObject,'String')) returns contents of Fstop1_edit as a double
% --- Executes during object creation, after setting all properties.
function Fstop1_edit_CreateFcn(hObject, eventdata, handles)
% hObject handle to Fstop1_edit (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
function Fpass1_edit_Callback(hObject, eventdata, handles)
% hObject handle to Fpass1_edit (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 Fpass1_edit as text
% str2double(get(hObject,'String')) returns contents of Fpass1_edit as a double
% --- Executes during object creation, after setting all properties.
function Fpass1_edit_CreateFcn(hObject, eventdata, handles)
% hObject handle to Fpass1_edit (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
function Fpass2_edit_Callback(hObject, eventdata, handles)
% hObject handle to Fpass2_edit (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 Fpass2_edit as text
% str2double(get(hObject,'String')) returns contents of Fpass2_edit as a double
% --- Executes during object creation, after setting all properties.
function Fpass2_edit_CreateFcn(hObject, eventdata, handles)
% hObject handle to Fpass2_edit (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
function Fstop2_edit_Callback(hObject, eventdata, handles)
% hObject handle to Fstop2_edit (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 Fstop2_edit as text
% str2double(get(hObject,'String')) returns contents of Fstop2_edit as a double
% --- Executes during object creation, after setting all properties.
function Fstop2_edit_CreateFcn(hObject, eventdata, handles)
% hObject handle to Fstop2_edit (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 selection change in filter_type.
function filter_type_Callback(hObject, eventdata, handles)
% hObject handle to filter_type (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
global response;
val=get(hObject,'Value');
switch val
case 1
set(handles.type_information,'String','Lowpass');
set(handles.Fstop1,'String','Fstop');
set(handles.Fpass1,'String','Fpass');
set(handles.Fpass2,'Visible','off');%当为低通滤波器时屏蔽Fpass2 Fstop2并把Fstop1 Fpass1设为Fstop Fpass
set(handles.Fstop2,'Visible','off');
set(handles.Fpass2_edit,'Visible','off');
set(handles.Fstop2_edit,'Visible','off');
response=1;
case 2
set(handles.type_information,'String','Highpass');
set(handles.Fstop1,'String','Fstop');
set(handles.Fpass1,'String','Fpass');
set(handles.Fpass2,'Visible','off');%当为高通滤波器时屏蔽Fpass2 Fstop2并把Fstop1 Fpass1设为Fstop Fpass
set(handles.Fstop2,'Visible','off');
set(handles.Fpass2_edit,'Visible','off');
set(handles.Fstop2_edit,'Visible','off');
response=2;
case 3
set(handles.type_information,'String','Bandpass');
set(handles.Fstop1,'String','Fstop1');
set(handles.Fpass1,'String','Fpass1');
set(handles.Fpass2,'Visible','on');%当为高通滤波器时屏蔽Fpass2 Fstop2并把Fstop1 Fpass1设为Fstop Fpass
set(handles.Fstop2,'Visible','on');
set(handles.Fpass2_edit,'Visible','on');
set(handles.Fstop2_edit,'Visible','on');
response=3;
case 4
set(handles.type_information,'String','Bandstop');
set(handles.Fstop1,'String','Fstop1');
set(handles.Fpass1,'String','Fpass1');
set(handles.Fpass2,'Visible','on');%当为高通滤波器时屏蔽Fpass2 Fstop2并把Fstop1 Fpass1设为Fstop Fpass
set(handles.Fstop2,'Visible','on');
set(handles.Fpass2_edit,'Visible','on');
set(handles.Fstop2_edit,'Visible','on');
response=4;
otherwise
set(handles.type_information,'String','Lowpass');
set(handles.Fstop1,'String','Fstop');
set(handles.Fpass1,'String','Fpass');
set(handles.Fpass2,'Visible','off');%当为低通滤波器时屏蔽Fpass2 Fstop2并把Fstop1 Fpass1设为Fstop Fpass
set(handles.Fstop2,'Visible','off');
set(handles.Fpass2_edit,'Visible','off');
set(handles.Fstop2_edit,'Visible','off');
response=1;
end
guidata(hObject, handles);
% Hints: contents = cellstr(get(hObject,'String')) returns filter_type contents as cell array
% contents{get(hObject,'Value')} returns selected item from filter_type
% --- Executes during object creation, after setting all properties.
function filter_type_CreateFcn(hObject, eventdata, handles)
% hObject handle to filter_type (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 && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
set(hObject,'BackgroundColor','white');
end
% --- Executes on selection change in analog_filter.
function analog_filter_Callback(hObject, eventdata, handles)
% hObject handle to analog_filter (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
global analog;
val_1=get(hObject,'Value');
switch val_1
case 1
%set(handles.analog_filter,'String','Butterworth');
analog=1;set(handles.function_value,'String','Butterworth');%反馈IIR滤波器设计所用到的函数
case 2
set(handles.function_value,'String','ChebyshevI');
analog=2;
case 3
set(handles.function_value,'String','ChebyshevII');
analog=3;
otherwise
set(handles.function_value,'String','Butterworth');
analog=1;
end
guidata(hObject, handles);
% Hints: contents = cellstr(get(hObject,'String')) returns analog_filter contents as cell array
% contents{get(hObject,'Value')} returns selected item from analog_filter
% --- Executes during object creation, after setting all properties.
function analog_filter_CreateFcn(hObject, eventdata, handles)
% hObject handle to analog_filter (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 && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
set(hObject,'BackgroundColor','white');
end
% --- Executes on selection change in digital_filter.
function digital_filter_Callback(hObject, eventdata, handles)
% hObject handle to digital_filter (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
global digital;
val_2=get(hObject,'Value');
set(handles.order_information,'String','order');
switch val_2
case 1
% set(handles.digital_filter,'String','window');
digital=1; set(handles.method_value,'String','window function');%反馈IIR滤波器的方法
set(handles.view_window,'Enable','on');
set(handles.window_function,'Enable','on');
set(handles.specify_order,'Enable','on'); set(handles.specify_order,'Value',0);
set(handles.custom_order,'Enable','on');set(handles.custom_order,'String','');
set(handles.min_order,'Enable','on');set(handles.min_order,'Value',0);
if(get(handles.FIR_button,'Value'))
set(handles.order,'Enable','off');end;
case 2
% set(handles.digital_filter,'String','frequency response invariance');
digital=2; set(handles.method_value,'String','FSI');
set(handles.view_window,'Enable','off');
set(handles.window_function,'Enable','off');
set(handles.order,'Enable','on');
if(get(handles.FIR_button,'Value')==1)
set(handles.specify_order,'Enable','off');
set(handles.custom_order,'Enable','off');
set(handles.min_order,'Enable','off');
set(handles.window_function,'Enable','off');
set(handles.view_window,'Enable','off');
set(handles.order_information,'String','sample');
end
otherwise
% set(handles.digital_filter,'String','window');
digital=1;set(handles.method_value,'String','window function');
end
guidata(hObject, handles);
% Hints: contents = cellstr(get(hObject,'String')) returns digital_filter contents as cell array
% contents{get(hObject,'Value')} returns selected item from digital_filter
% --- Executes during object creation, after setting all properties.
function digital_filter_CreateFcn(hObject, eventdata, handles)
% hObject handle to digital_filter (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 && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
set(hObject,'BackgroundColor','white');
end
% --- Executes on selection change in window_function.
function window_function_Callback(hObject, eventdata, handles)
global window1;
val_4=get(hObject,'Value');
switch val_4
case 1
window1=1;set(handles.function_value,'String','Hamming');%反馈函数信息
case 2
window1=2; set(handles.function_value,'String','Blackman');
case 3
window1=3;set(handles.function_value,'String','Hann');
case 4
window1=4; set(handles.function_value,'String','Rectangular');
otherwise
% set(handles.digital_filter,'String','window');
window1=1;
end
guidata(hObject, handles);
% hObject handle to window_function (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB
% handles structure with handles and user data (see GUIDATA)
% Hints: contents = cellstr(get(hObject,'String')) returns window_function contents as cell array
% contents{get(hObject,'Value')} returns selected item from window_function
% --- Executes during object creation, after setting all properties.
function window_function_CreateFcn(hObject, eventdata, handles)
% hObject handle to window_function (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 && isequal(get(hObject,'BackgroundColor'), get(0,'defaultUicontrolBackgroundColor'))
set(hObject,'BackgroundColor','white');
end
% --- Executes on button press in view_window.
function Apass_Callback(hObject, eventdata, handles)
% hObject handle to Apass (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 Apass as text
% str2double(get(hObject,'String')) returns contents of Apass as a double
% --- Executes during object creation, after setting all properties.
function Apass_CreateFcn(hObject, eventdata, handles)
% hObject handle to Apass (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
function Astop_Callback(hObject, eventdata, handles)
% hObject handle to Astop (see GCBO)
% eventdata reserved - to be defined in a future version of MATLAB

3 仿真结果

​

4 参考文献

[1]洪灿梅, 刘爱莲, 刘名扬,等. FIR滤波器与IIR滤波器去噪效果对比研究[J]. 微型机与应用, 2015, 34(21):4.

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