一、简介

1 案例背景

2 理论基础

2.1 图像灰度化

（1）分量值

（2）最大值

（3）平均值

（4）加权平均值

F.(i.j)=0.299R(i，j)+0.587G(i，j)+0.114*B(i，j)

2.2 图像滤波

(1)定位

(2)计算

(3)赋值

2.3 图像增强

2.4 图像二值化

(1)全局阈值是最常见的阈值计算方法，它一般以图像的直方图或灰度空间分布为基础来确定一个阈值，进而实现灰度图像的二值化。特别是当图像的灰度直方图分布呈双峰时，全局阈值法可以明显地将目标和背景分量，得到较为理想的图像分割效果。但裂缝图像一般具有光照不均匀、噪声干扰等特点，其灰度直方图往往不会呈双峰分布，因此全局阈值分割方法效果较差。
(2)基本自适应阀值是一种比较基础的图像自适应分割方法，它一般以图像像素自身及其邻域灰度变化的特征为基础进行阈值分割，进而实现灰度图像的二值化。该方法充分考虑了每个像素邻域的特征，所以一般能更好地突出目标和背景的边界。

3 程序实现

二、部分源代码

function varargout = Gui_Main(varargin)
% GUI_MAIN M-file for Gui_Main.fig
%      GUI_MAIN, by itself, creates a new GUI_MAIN or raises the existing
%      singleton*.
%
%      H = GUI_MAIN returns the handle to a new GUI_MAIN or the handle to
%      the existing singleton*.
%
%      GUI_MAIN('CALLBACK',hObject,eventData,handles,...) calls the local
%      function named CALLBACK in GUI_MAIN.M with the given input arguments.
%
%      GUI_MAIN('Property','Value',...) creates a new GUI_MAIN or raises the
%      existing singleton*.  Starting from the left, property value pairs are
%      applied to the GUI before Gui_Main_OpeningFcn gets called.  An
%      unrecognized property name or invalid value makes property application
%      stop.  All inputs are passed to Gui_Main_OpeningFcn via varargin.
%
%      *See GUI Options on GUIDE's Tools menu.  Choose "GUI allows only one
%      instance to run (singleton)".
%

% Edit the above text to modify the response to help Gui_Main

% Begin initialization code - DO NOT EDIT
gui_Singleton = 1;
gui_State = struct('gui_Name',       mfilename, ...
'gui_Singleton',  gui_Singleton, ...
'gui_OpeningFcn', @Gui_Main_OpeningFcn, ...
'gui_OutputFcn',  @Gui_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 Gui_Main is made visible.
function Gui_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 Gui_Main (see VARARGIN)

% Choose default command line output for Gui_Main
handles.output = hObject;
handles.Result = [];
handles.File = [];
% Update handles structure
guidata(hObject, handles);
clc; warning off all;
InitAxes(handles);

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

% --- Outputs from this function are returned to the command line.
function varargout = Gui_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;

% --- Executes on button press in pushbuttonOpenFile.
function pushbuttonOpenFile_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonOpenFile (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({'*.jpg;*.tif;*.png;*.gif;*.bmp','All Image Files';...
'*.*','All Files' },'载入图像',...
fullfile(pwd, 'images'));
if isequal(filename, 0) || isequal(pathname, 0)
return;
end
Result = Process_Main(I);
handles.File = fullfile(pathname, filename);
handles.Result = Result;
guidata(hObject, handles);
InitAxes(handles)
axes(handles.axes1); imshow(handles.Result.Image); title('原图像');

% --- Executes on button press in pushbuttonHisteq.
function pushbuttonHisteq_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonHisteq (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
if ~isempty(handles.Result)
axes(handles.axes1); imshow(handles.Result.Image); title('原图像');
axes(handles.axes2); imshow(handles.Result.hist); title('直方图均衡化图像');
end

% --- Executes on button press in pushbuttonMedfilt.
function pushbuttonMedfilt_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonMedfilt (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
if ~isempty(handles.Result)
axes(handles.axes1); imshow(handles.Result.Image); title('原图像');
axes(handles.axes2); imshow(handles.Result.Medfilt); title('中值滤波图像');
end

% --- Executes on button press in pushbuttonBw.
function pushbuttonBw_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonBw (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
if ~isempty(handles.Result)
axes(handles.axes1); imshow(handles.Result.Image); title('原图像');
axes(handles.axes2); imshow(handles.Result.Bw); title('二值图像');
end

% --- Executes on button press in pushbuttonEnance.
function pushbuttonEnance_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonEnance (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
if ~isempty(handles.Result)
axes(handles.axes1); imshow(handles.Result.Image); title('原图像');
axes(handles.axes2); imshow(handles.Result.Enance); title('增强图像');
end

% --- Executes on button press in pushbuttonBwfilter.
function pushbuttonBwfilter_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonBwfilter (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
if ~isempty(handles.Result)
axes(handles.axes1); imshow(handles.Result.Image); title('原图像');
axes(handles.axes2); imshow(handles.Result.Bw); title('二值图像');
axes(handles.axes3); imshow(handles.Result.BwFilter); title('二值图像滤波');
end

% --- Executes on button press in pushbuttonCrackRec.
function pushbuttonCrackRec_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonCrackRec (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
if ~isempty(handles.Result)
axes(handles.axes1); imshow(handles.Result.Image); title('原图像');
axes(handles.axes2); imshow(handles.Result.Bw); title('二值图像');
axes(handles.axes3); imshow(handles.Result.BwFilter); title('二值图像滤波');
axes(handles.axes4); imshow(handles.Result.CrackRec); title('裂缝识别');
end

% --- Executes on button press in pushbuttonCrackJudge.
function pushbuttonCrackJudge_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonCrackJudge (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
if ~isempty(handles.Result)
axes(handles.axes1); imshow(handles.Result.Image); title('原图像');
axes(handles.axes2); imshow(handles.Result.BwFilter); title('二值图像滤波');
axes(handles.axes3); imshow(handles.Result.CrackRec); title('裂缝识别');
axes(handles.axes4); imshow(handles.Result.CrackJudge); title('裂缝判断');
end

% --- Executes on button press in pushbuttonCrackLoc.
function pushbuttonCrackLoc_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonCrackLoc (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
if ~isempty(handles.Result)
axes(handles.axes1); imshow(handles.Result.Image); title('原图像');
axes(handles.axes2); imshow(handles.Result.CrackJudge); title('裂缝图像');
axes(handles.axes3); imshow(handles.Result.CrackJudge); title(handles.Result.str);
axes(handles.axes4); imshow(handles.Result.CrackJudge); title('裂缝标记图像');
hold on;
rectangle('Position', handles.Result.rect, 'EdgeColor', 'g', 'LineWidth', 2);
hold off;
end

% --- Executes on button press in pushbuttonProject.
function pushbuttonProject_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonProject (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
if ~isempty(handles.Result)
axes(handles.axes1); imshow(handles.Result.Image); title('原图像');
axes(handles.axes2); imshow(handles.Result.CrackJudge); title('裂缝图像');
axes(handles.axes3); plot(1:size(handles.Result.Image, 1), handles.Result.Projectr);
title('行投影');
axes(handles.axes4); plot(1:size(handles.Result.Image, 2), handles.Result.Projectc);
title('列投影');
end

% --- Executes on button press in pushbuttonClose.
function pushbuttonClose_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonClose (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
choice = questdlg('确定退出?', ...
'退出', ...
'是','否','否');
switch choice
case '是'
close;
otherwise
return;
end

% --- Executes on button press in pushbuttonSaveResult.
function pushbuttonSaveResult_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonSaveResult (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
try
if ~isempty(handles.File)
raw = [];
xlsfile = fullfile(pwd, 'Result/result.xls');
if exist(xlsfile, 'file')
end

F = [];
F{1, 1} = '文件名';
F{1, 2} = '阈值信息';
F{1, 3} = '面积信息';
F{1, 4} = '长度信息';
F{1, 5} = '最大宽度信息';
F{1, 6} = '最小宽度信息';
F{1, 7} = '形状信息';

F{2, 1} = handles.File;
F{2, 2} = handles.Result.BwTh;
F{2, 3} = handles.Result.BwArea;
F{2, 4} = handles.Result.BwLength;
F{2, 5} = handles.Result.BwWidthMax;
F{2, 6} = max(handles.Result.BwWidthMin,0.01);
F{2, 7} = handles.Result.str;

F = [raw; F];
xlswrite(xlsfile, F);

msgbox('保存结果成功！', '信息提示框');
end
catch
msgbox('保存结果失败，请检查程序！', '信息提示框');
end

% --- Executes on button press in pushbuttonBridge.
function pushbuttonBridge_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonBridge (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
if ~isempty(handles.Result)
axes(handles.axes1); imshow(handles.Result.Image); title('原图像');
axes(handles.axes2); imshow(handles.Result.BwFilter); title('二值图像滤波');
axes(handles.axes3); imshow(handles.Result.CrackJudge); title('裂缝判断');
axes(handles.axes4); imshow(handles.Result.CrackBridge); title('裂缝拼接');
end

% --- Executes on button press in pushbuttonSaveImage.
function pushbuttonSaveImage_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonSaveImage (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
[filename, pathname] = uiputfile({'*.jpg;*.tif;*.png;*.gif','All Image Files';...
'*.*','All Files' },'Save Image',...
fullfile(pwd, 'Result/result.png'));
if ~isequal(filename, 0)
imwrite(handles.Result.BwEnd, fullfile(pathname, filename));
msgbox('保存图像成功！', '信息提示框');
end

% --- Executes on button press in pushbuttonDiplay.
function pushbuttonDiplay_Callback(hObject, eventdata, handles)
% hObject    handle to pushbuttonDiplay (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
if ~isempty(handles.File)
F = [];
F{1} = sprintf('文件名:%s', handles.File);
F{2} = sprintf('阈值信息%.2f', handles.Result.BwTh);
F{3} = sprintf('面积信息%.2f', handles.Result.BwArea);
F{4} = sprintf('长度信息%.2f', handles.Result.BwLength);
F{5} = sprintf('最大宽度信息%.2f', handles.Result.BwWidthMax);
F{6} = sprintf('最小宽度信息%.2f', max(handles.Result.BwWidthMin,0.01));
F{7} = sprintf('形状信息%s', handles.Result.str);
listdlg('PromptString', '参数显示:',...
'Name', '参数信息', ...
'ListSize', [300, 150], ...
'SelectionMode','single',...
'ListString', F);
end


四、matlab版本及参考文献

1 matlab版本
2014a

2 参考文献
[1] 蔡利梅.MATLAB图像处理——理论、算法与实例分析[M].清华大学出版社，2020.
[2]杨丹,赵海滨,龙哲.MATLAB图像处理实例详解[M].清华大学出版社，2013.
[3]周品.MATLAB图像处理与图形用户界面设计[M].清华大学出版社，2013.
[4]刘成龙.精通MATLAB图像处理[M].清华大学出版社，2015.