简介
在模式识别中一个最基本的方法，就是模板匹配法(template matching)，它基本上是一种统计识别方法。 为了在图像中检测出已知形状的目标物，我们使用这个目标物的形状模板（或窗口）与图像匹配，在约定的某种准则下检测出目标物图像，通常称其为模板匹配法。它能检测出图像中上线条、曲线、图案等等。它的应用包括：目标模板与侦察图像相匹配；文字识别和语音识别等。
原理
我们采用以下的算式来衡量模板T（m,n)与所覆盖的子图Sij（i,j)的关系，已知原始图像S(W,H)，如图所示：
利用以下公式衡量它们的相似性：
上述公式中第一项为子图的能量，第三项为模板的能量，都和模板匹配无关。第二项是模板和子图的互为相关，随（i,j）而改变。当模板和子图匹配时，该项由最大值。在将其归一化后，得到模板匹配的相关系数：
当模板和子图完全一样时，相关系数R(i,j) = 1。在被搜索图S中完成全部搜索后，找出R的最大值Rmax(im,jm)，其对应的子图Simjm即位匹配目标。显然，用这种公式做图像匹配计算量大、速度慢。我们可以使用另外一种算法来衡量T和Sij的误差，其公式为：
计算两个图像的向量误差，可以增加计算速度，根据不同的匹配方向选取一个误差阀值E0，当E(i,j)>E0时就停止该点的计算，继续下一点的计算。
最终的实验证明，被搜索的图像越大，匹配的速度越慢；模板越小，匹配的速度越快；阀值的大小对匹配速度影响大；
改进的模板匹配算法
将一次的模板匹配过程更改为两次匹配；
第一次匹配为粗略匹配。取模板的隔行隔列数据，即1/4的模板数据，在被搜索土上进行隔行隔列匹配，即在原图的1/4范围内匹配。由于数据量大幅减少，匹配速度显著提高。同时需要设计一个合理的误差阀值E0：
E0 = e0 * (m + 1) / 2 * (n + 1) / 2
式中：e0为各点平均的最大误差，一般取40~50即可；
m,n为模板的长宽；
第二次匹配是精确匹配。在第一次误差最小点（imin, jmin)的邻域内，即在对角点为（imin -1, jmin -1), (Imin + 1, jmin + 1)的矩形内，进行搜索匹配，得到最后结果。
流程图
算法实现的关键问题是进行匹配，求最小距离，其解决方法是和训练集的样品逐一进行距离的计算，最后找出最相邻的样品得到类别号。
function varargout = NumDemo(varargin)% NUMDEMO MATLAB code for NumDemo.fig%NUMDEMO, by itself, creates a new NUMDEMO or raises the existing%singleton*.%%H = NUMDEMO returns the handle to a new NUMDEMO or the handle to%the existing singleton*.%%NUMDEMO('CALLBACK',hObject,eventData,handles,...) calls the local%function named CALLBACK in NUMDEMO.M with the given input arguments.%%NUMDEMO('Property','Value',...) creates a new NUMDEMO or raises the%existing singleton*. Starting from the left, property value pairs are%applied to the GUI before NumDemo_OpeningFcn gets called. An%unrecognized property name or invalid value makes property application%stop. All inputs are passed to NumDemo_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 NumDemo% Last Modified by GUIDE v2.5 28-Apr- 11:22:33% Begin initialization code - DO NOT EDITgui_Singleton = 1;gui_State = struct('gui_Name', mfilename, ...'gui_Singleton', gui_Singleton, ...'gui_OpeningFcn', @NumDemo_OpeningFcn, ...'gui_OutputFcn', @NumDemo_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 NumDemo is made visible.function NumDemo_OpeningFcn(hObject, ~, 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 NumDemo (see VARARGIN)% Choose default command line output for NumDemohandles.output = hObject;% Update handles structureguidata(hObject, handles);% UIWAIT makes NumDemo wait for user response (see UIRESUME)% uiwait(handles.figure1);% --- Outputs from this function are returned to the command line.function varargout = NumDemo_OutputFcn(~, ~, 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;axis([0 250 0 250]);clc;% --- Executes on mouse press over figure background, over a disabled or% --- inactive control, or over an axes background.function figure1_WindowButtonDownFcn(~, ~, 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 ButtonDown pos1if strcmp(get(gcf, 'SelectionType'), 'normal')ButtonDown = 1;pos1 = get(handles.axes1, 'CurrentPoint');end% --- Executes on mouse motion over figure - except title and menu.function figure1_WindowButtonMotionFcn(~, ~, 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 ButtonDown pos1if(ButtonDown == 1)pos = get(handles.axes1,'CurrentPoint');line([pos1(1,1) pos(1,1)], [pos1(1,2) pos(1,2)], 'Color','Black','LineStyle','-', 'LineWidth',8,'Marker','.', 'MarkerSize',20);pos1 = pos;end% --- Executes on mouse press over figure background, over a disabled or% --- inactive control, or over an axes background.function figure1_WindowButtonUpFcn(~, ~, ~)% 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 ButtonDownButtonDown = 0;% --- Executes on button press in pushbutton_clear.function pushbutton_clear_Callback(~, ~, handles)% hObject handle to pushbutton_clear (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)%cla;cla(handles.axes1);% --- Executes on button press in pushbutton_save.function pushbutton_save_Callback(~, ~, handles)% hObject handle to pushbutton_save (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)[f, p] = uiputfile({'*.bmp'},'Save Image');str = strcat(p, f);px = getframe(handles.axes3);curImg = frame2im(px);imwrite(curImg, str,'bmp');% --- Executes on button press in pushbutton_classify.function pushbutton_classify_Callback(~, ~, handles)% hObject handle to pushbutton_classify (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)%strSample = 'Data.mat';cla(handles.axes4,handles.axes5,handles.axes6);load 'Data.mat';I1=handles.I1;curFea = GetFeature(I1);I2 = Normalize_Img(I1);bw1 = Bw_Img(I1);bw2 = Thin_Img(bw1);bw = bw2;sz = size(bw);[r, c] = find(bw==1);rect = [min(c) min(r) max(c)-min(c) max(r)-min(r)];vs = rect(1)+rect(3)*[5/12 1/2 7/12];hs = rect(2)+rect(4)*[1/3 1/2 2/3];pt1 = [rect(1:2); rect(1:2)+rect(3:4)];pt2 = [rect(1)+rect(3) rect(2); rect(1) rect(2)+rect(4)];k1 = (pt1(1,2)-pt1(2,2)) / (pt1(1,1)-pt1(2,1));x1 = 1:sz(2);y1 = k1*(x1-pt1(1,1)) + pt1(1,2);k2 = (pt2(1,2)-pt2(2,2)) / (pt2(1,1)-pt2(2,1));x2 = 1:sz(2);y2 = k2*(x2-pt2(1,1)) + pt2(1,2);axes(handles.axes4);imshow(I2,[]); handles.I2 = I2;hold on;h = rectangle('Position', [rect(1:2)-1 rect(3:4)+2], 'EdgeColor', 'r', 'LineWidth', 2);legend(h, '数字区域标记', 'Location', 'South');axes(handles.axes5);imshow(bw1,[]);handles.bw1 = bw1;axes(handles.axes6);imshow(bw,[],'Border', 'Loose');handles.bw = bw;hold on;h = [];for i = 1 : length(hs)h = [h plot([1 sz(2)], [hs(i) hs(i)], 'r-')];endfor i = 1 : length(vs)h = [h plot([vs(i) vs(i)], [1 sz(1)], 'g-')];endh = [h plot(x1, y1, 'y-')];h = [h plot(x2, y2, 'm-')];legend([h(1) h(4) h(7) h(8)], {'水平线', '竖直线', '左对角线', '右对角线'}, 'Location', 'BestOutside');hold off;%yLabel = euclid(curFea);yLabel = MaskRecon(Data, curFea);h = warndlg(num2str(yLabel),'识别结果');% --- Executes on mouse press over axes background.function axes1_ButtonDownFcn(hObject, eventdata, handles)% hObject handle to axes1 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% --- If Enable == 'on', executes on mouse press in 5 pixel border.% --- Otherwise, executes on mouse press in 5 pixel border or over pushbutton_clear.function pushbutton_clear_ButtonDownFcn(hObject, eventdata, handles)% hObject handle to pushbutton_clear (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% --- 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)[FileName,PathName,FilterIndex] = uigetfile({'*.jpg;*.tif;*.png;*.gif', ...'所有图像文件';...'*.*','所有文件' },'载入数字图像',...'.\\images\\手写数字\\t0.jpg');if isequal(FileName, 0) || isequal(PathName, 0)return;endfileName = fullfile(PathName, FileName);I = imread(fileName);axes(handles.axes2);imshow(I);handles.I = I;guidata(hObject, handles);% --- Executes on button press in pushbutton5.function pushbutton5_Callback(hObject, eventdata, handles)% hObject handle to pushbutton5 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)I = handles.I;axes(handles.axes2);I1 = imcrop(I);axes(handles.axes3);imshow(I1);handles.I1 = I1;guidata(hObject, handles);% --- Executes on button press in pushbutton6.function pushbutton6_Callback(hObject, eventdata, handles)% hObject handle to pushbutton6 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)% --- Executes on button press in pushbutton7.function pushbutton7_Callback(hObject, eventdata, handles)% hObject handle to pushbutton7 (see GCBO)% eventdata reserved - to be defined in a future version of MATLAB% handles structure with handles and user data (see GUIDATA)I = getframe(handles.axes1);handles.I=I;I1 = frame2im(I);axes(handles.axes3);imshow(I1);handles.I1 = I1;guidata(hObject, handles);
