一、简介

Fisher分类器用于解决二类线性可分问题。

Fisher准则基本原理：找到一个最合适的投影轴，使两类样本在该轴上投影之间的距离尽可能远，而每一类样本的投影尽可能紧凑，从而使分类效果为最佳。

例如上图中：通过将方块点和圆点向w1投影，然后再在设置合适的阈值即可将方块和圆点分离。

二、源代码

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

% Last Modified by GUIDE v2.5 02-Apr-2019 15:37:29

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct(\'gui_Name\',       mfilename, ...
                   \'gui_Singleton\',  gui_Singleton, ...
                   \'gui_OpeningFcn\', @main_gui_OpeningFcn, ...
                   \'gui_OutputFcn\',  @main_gui_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_gui is made visible.
function main_gui_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_gui (see VARARGIN)
% set( handles.axes1, \'visible\', \'off\' );
% set( handles.axes1, \'box\', \'on\' );
global W W0;
load W 
load W0

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

% Update handles structure
guidata(hObject, handles);

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


% --- Outputs from this function are returned to the command line.
function varargout = main_gui_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 mouse press over figure background, over a disabled or
% --- inactive control, or over an axes background.
function figure1_WindowButtonDownFcn(hObject, eventdata, handles)
% hObject    handle to figure1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
global draw_enable;  %定义一个标志，1表示绘图，0表示停止绘图
global x;
global y;
draw_enable=1;
if draw_enable
    position=get(gca,\'currentpoint\');  %gca（获取当前坐标轴的句柄）
    x(1)=position(1);
    y(1)=position(3);
end


% --- Executes on mouse motion over figure - except title and menu.
function figure1_WindowButtonMotionFcn(hObject, eventdata, handles)
% hObject    handle to figure1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
global draw_enable;
global x;
global y;
global h1;
if draw_enable==1
    position=get(gca,\'currentpoint\');
    x(2)=position(1);
    y(2)=position(3);
    h1=line(x,y,\'LineWidth\',25,\'color\',\'k\',\'Linestyle\',\'-.\');
    x(1)=x(2);
    y(1)=y(2);   %鼠标移动，随时更新数据
end


% --- Executes on mouse press over figure background, over a disabled or
% --- inactive control, or over an axes background.
function figure1_WindowButtonUpFcn(hObject, eventdata, handles)
% hObject    handle to figure1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
global draw_enable;
    draw_enable=0;

function num_Callback(hObject, eventdata, handles)
% hObject    handle to 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 num as text
%        str2double(get(hObject,\'String\')) returns contents of num as a double


% --- Executes during object creation, after setting all properties.
function num_CreateFcn(hObject, eventdata, handles)
% hObject    handle to 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 pushbutton1.
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 W
global W0
img=getframe(handles.axes1);
img=imresize(img.cdata,[28,28]);
img=im2bw(img,graythresh(img)); 
img=~img;
axes(handles.axes2);
img1=~img;
imshow(img1);%img1为预览图像
%计算概率
for cnt=1:4
    for cnt2=1:4
        Atemp=sum(img(((cnt*7-6):(cnt*7)),((cnt2*7-6):(cnt2*7))));%10*10box
        lett((cnt-1)*4+cnt2)=sum(Atemp);
    end

三、运行结果

四、备注

版本：2014a