hey ,I make GUI Application in matlab for brain tumor segmentation and I have this problem

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

% Last Modified by GUIDE v2.5 06-Jul-2019 01:31:00

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

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

% Update handles structure
guidata(hObject, handles);

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


% --- Outputs from this function are returned to the command line.
function varargout = 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 load.
function load_Callback(hObject, eventdata, handles)
% hObject    handle to load (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
global im im2
[path,user_cancel]=imgetfile();
    if user_cancel
        msbox(sprintf('Invalide selection'),'Error','Error');
        return
    end
    im=imread(path); %read the path of the image 
    im=im2double(im); %convert to double
    im2=im; %Backup of image
    axes(handles.axes1);
    imshow(im)
    title('\fontsize{18}\color[rgb]{0.635 0.078 0.184}Patient''s Brain')
% --- Executes on button press in detect.
function detect_Callback(hObject, eventdata, handles)
% hObject    handle to detect (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
global im 
axes(handles.axes2);
bw=imbinarize(img,0.7);  %Thresholding value  if less than 0.7 color is black ,if morr than 0.7 color is white
label = bwlabel(logical(bw)); %area of tumor
stats = regionprops(label , 'Solidity', 'Area'); % properties of healthy region
denisty = [stats.Solidity];
area = [stats.Area];

high_dense_area = denisty > 0.5 ;  %Area of tumor
max_area = max(area(high_dense_area));    %max area 
tumor_label = find(area == max_area); %place of tumor
tumor = ismember(label, tumor_label);

se = strel('square',5);
tumor = imdilate(tumor,se);
B= bwboundaries(tumor,'noholes');
imshow(im);
hold on 
for i=1:length(B)
    plot(B{i}(:,2), B{i}(:,1),'y','linewidth',1.45)
end
    title('\fontsize{18}\color[rgb]{0.635 0.078 0.184}Detect Brain')
hold off


% --------------------------------------------------------------------
function about_Callback(hObject, eventdata, handles)
% hObject    handle to about (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)


% --------------------------------------------------------------------
function author_Callback(hObject, eventdata, handles)
% hObject    handle to author (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
msgbox(sprintf('Name:Aml omar\nEmail:[e-mail]\nID1100602'),'Author','Help')

and problem is

Error in GUi (line 42)

gui_mainfcn(gui_State, varargin{:});

Error in

matlab.graphics.internal.figfile.FigFile/read>@(hObject,eventdata)GUi('detect_Callback',hObject,eventdata,guidata(hObject))

Error while evaluating UIControl Callback.

Answer 1

[Geoff Hayes]

Mohamed - you haven't copied and pasted the full error message, but looking at the code to your callback

function detect_Callback(hObject, eventdata, handles)
% hObject    handle to detect (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
global im 
axes(handles.axes2);
bw=imbinarize(img,0.7);  %Threshol

there is a global variable named im but you are passing img into the imbinarize function. I suspect that you mean to do

bw=imbinarize(im,0.7);  %Threshol

instead.

Please note that using the handles structure to store user data is an alternative to using global variables.