已知GUI界面中有名为axes2的图像显示区域， GUI界面中有名为zhifangtulei的按钮。要求matlabGUI界面续写下面基于retinex方法和直方图方法的图像增强完整代码并且通过调试：global s if ~isfield(handles, 'img') msgbox('请先选择图像！', 'error'); return end % 读取图像 im = handles.img; % 进行retinex增强 im_retinex = retinex(im); % 显示增强后的图像 axes(handles.axes2); imshow(im_retinex); % 保存增强后的图像 [pathname, filename, ext] = fileparts(s); imwrite(im_retinex, [pathname, filesep, 'retinex_', filename, ext]); % 保存数据 handles.im_retinex = im_retinex; guidata(hObject, handles); function im_retinex = retinex(im)和function zhifangtulei_Callback(hObject, eventdata, handles)

下面是基于retinex方法和直方图方法的图像增强完整代码：

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

% Last Modified by GUIDE v2.5 25-Jul-2021 16:47:17

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

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

% Update handles structure
guidata(hObject, handles);

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


% --- Outputs from this function are returned to the command line.
function varargout = image_enhancement_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 button press in open_btn.
function open_btn_Callback(hObject, eventdata, handles)
% hObject    handle to open_btn (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% 打开图像
[filename, pathname] = uigetfile({'*.bmp;*.jpg;*.jpeg;*.png;*.tif;*.tiff', 'Image Files (*.bmp, *.jpg, *.jpeg, *.png, *.tif, *.tiff)'}, '请选择一张图片');
if isequal(filename,0) || isequal(pathname,0)
    msgbox('未选择图片', 'warn');
    return;
end
s = fullfile(pathname, filename);
im = imread(s);
if size(im, 3) == 3
    im = rgb2gray(im);
end
% 显示原始图像
axes(handles.axes1);
imshow(im);
% 保存数据
handles.img = im;
guidata(hObject, handles);


% --- Executes on button press in retinex_btn.
function retinex_btn_Callback(hObject, eventdata, handles)
% hObject    handle to retinex_btn (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

if ~isfield(handles, 'img')
    msgbox('请先选择图像！', 'error');
    return
end

% 读取图像
im = handles.img;

% 进行retinex增强
im_retinex = retinex(im);

% 显示增强后的图像
axes(handles.axes2);
imshow(im_retinex);

% 保存增强后的图像
[pathname, filename, ext] = fileparts(s);
imwrite(im_retinex, [pathname, filesep, 'retinex_', filename, ext]);

% 保存数据
handles.im_retinex = im_retinex;
guidata(hObject, handles);

% 定义retinex函数
function im_retinex = retinex(im)
% 进行retinex增强
im_log = log(double(im) + 1);
im_mean = mean2(im_log);
im_retinex = exp(im_log - im_mean);

% --- Executes on button press in zhifangtulei_btn.
function zhifangtulei_btn_Callback(hObject, eventdata, handles)
% hObject    handle to zhifangtulei_btn (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

if ~isfield(handles, 'img')
    msgbox('请先选择图像！', 'error');
    return
end

% 读取图像
im = handles.img;

% 进行直方图均衡化增强
im_zhifangtulei = histeq(im);

% 显示增强后的图像
axes(handles.axes2);
imshow(im_zhifangtulei);

% 保存增强后的图像
[pathname, filename, ext] = fileparts(s);
imwrite(im_zhifangtulei, [pathname, filesep, 'zhifangtulei_', filename, ext]);

% 保存数据
handles.im_zhifangtulei = im_zhifangtulei;
guidata(hObject, handles);

% --- Executes on button press in close_btn.
function close_btn_Callback(hObject, eventdata, handles)
% hObject    handle to close_btn (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

% 关闭窗口
close(handles.figure1);

需要注意的是，在retinex_btn_Callback和zhifangtulei_btn_Callback中，增强后的图像保存路径和文件名的命名方式不一样，因为需要区分不同的增强方法。