Using GUI, use one push button as an image browser and another to process the image that was chosen?

Hi I'm creating a GUI for part of an image processing project at university. To this point I've created a push button which allows me to browse through my working directory and select either a 'jpg' or 'bmp' image: below is the code:

% --- Executes on button press in pushbutton1(Image Browser).
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)
[filename pathname] = uigetfile({'*.jpg';'*.bmp'},'File Selector');
image = strcat(pathname, filename);
axes(handles.axes1);
imshow(image)
set(handles.edit1,'string',filename);
set(handles.edit2,'string',image);

I'm looking to create another push button which will plot a histogram of the image I read in, I'm not sure how to define the image under the new function as the image that was chosen previously, could any one help, below is the code I have at the minute for the histogram push button but it is giving out errors;

% --- Executes on button press in pushbutton2 (Histogram plot).
function pushbutton2_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton2 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
axes(handles.axes1);
histogram(double(image(:)),'Normalization','pdf');

could any one help me out?

Answer 1

[Geoff Hayes]

Sean - image is the name of a built-in MATLAB function so it is not a good idea to name your variable image and so you should rename it to something else.

As for having your second callback be "aware" of the image that was chosen in the first callback, note the comment for the handles structure input

 % handles    structure with handles and user data (see GUIDATA)

You can update this structure with the image (user data) in the first callback so that any other callbacks that receive handles as an input will have access to it. Try something like

 function pushbutton1_Callback(hObject, eventdata, handles)

 [filename pathname] = uigetfile({'*.jpg';'*.bmp'},'File Selector');
 handles.myImage = strcat(pathname, filename);
 axes(handles.axes1);
 imshow(handles.myImage)
 set(handles.edit1,'string',filename);
 set(handles.edit2,'string',image);

 % save the updated handles object
 guidata(hObject,handles);

In your second callback, just reference the loaded image as handles.myImage as

 function pushbutton2_Callback(hObject, eventdata, handles)

 if isfield(handles,'myImage')
     % do stuff
 end

Try the above and see what happens!

[Sean]

Hi sorry for only getting back now I was working all day Sunday and had class all day today. I've used the code below, following the help you have me above:

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)
%%Initial Method
[filename pathname] = uigetfile({'*.jpg';'*.bmp'},'File Selector');
MyImage = strcat(pathname, filename);
axes(handles.axes1);
imshow(MyImage)
set(handles.edit1,'string',filename);
set(handles.edit2,'string',MyImage);
 % save the updated handles object
 guidata(hObject,handles);

    function pushbutton2_Callback(hObject, eventdata, handles)
    % hObject    handle to pushbutton2 (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,'MyImage')
         axes(handles.axes2);
         B=histogram(double(MyImage(:)),'Normalization','pdf');
         imshow(B)

   end

I've added in another axes so I can plot the histogram beside the original image. No errors appear, however when I press the Histogram push button nothing appears in the axes. Is there something I don't have in the code for my second function??

Thanks, Sean

[Sean]

I got it working! thanks , I made a typo with respect to you correction! Thanks for the help again, much appreciated.

[ayushi]

sir m not getting how to do that suppose i have a following code for button1:

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)
set(handles.edit3, 'Visible','off');
% Build the complete filename
[filename, pathname]=uigetfile( {'*.jpg';'*.jpeg';'*.gif';'*.png';'*.bmp'},'Select file'); 
 MyImage = strcat(pathname, filename);
%This code checks if the user pressed cancel on the dialog.
        if isequal(filename,0) || isequal(pathname,0)
            uiwait(msgbox ('User pressed cancel','failed','modal')  )
            hold on;
        else
            uiwait(msgbox('User selected image sucessfully','sucess','modal'));
            hold off;
             imshow(MyImage,'Parent',handles.axes2);
        end
handles.output = hObject;
guidata(hObject, handles);
and in second button i want to apply further processing on the browsed image like:

    function pushbutton2_Callback(hObject, eventdata,handles)
        %hold off;
        if isfield(handles,'MyImage')
            axes2(handles.axes);
            hold on;
            % Convert RGB image to gray scale image
         image=rgb2gray(MyImage);
         hold off;
         imshow(image,'Parent',handles.axes2); 
         %gaussian filter:
    hold on;
    Iblur1 = imgaussfilt(image,2);
    Iblur2 = imgaussfilt(image,4);
    Iblur3 = imgaussfilt(image,8);
    Display the original image and all the filtered images.
    %figure(3)
    hold off;
    imshow(image,handles.axes2)
    %title('Original image')
    hold on;
    %figure(4)
    hold off;
    imshow(Iblur1,handles.axes2)
    %title('Smoothed image, \sigma = 2')
    hold on;
    %figure(5)
    hold off;
    imshow(Iblur2,handles.axes2)
    %title('Smoothed image, \sigma = 4')
    hold on;
    %figure(6)
    hold off;
    imshow(Iblur3,handles.axes2)
    %title('Smoothed image, \sigma = 8')
          end 
its not showing image after processing in axes why?how can we resolve that error?please guide

[Geoff Hayes]

ayushi - please don't duplicate your comments (see http://www.mathworks.com/matlabcentral/answers/282109-suppose-there-are-two-buttons-in-a-gui-and-from-first-button-i-browsed-an-image-and-now-i-want-to-us). If you have a question, then post a question, but don't comment with the same text in several places.

Answer 2

[Ka Mirul]

I found a video that help me, it is about creating GUI to browse an image and display the image and its name. It should help you : https://youtu.be/7EmFShs5y9I

Answer 3

[Maria]

how many edit box will we need/