How can I share image data between callbacks?

The code that I am using is :

function pushbutton1_Callback(hObject, eventdata, handles)
handles.pushbutton1 = imread(uigetfile);
axes(handles.axes1);
imshow(handles.pushbutton1);
guidata(hObject, handles);

function pushbutton2_Callback(hObject, eventdata, handles)
handles = guidata(hObject);
handles.y = rgb2gray(imread(handles.pushbutton1));
axes(handles.axes1);
imshow(handles.y);
guidata(hObject,handles);

I need to use the image that I have loaded using pushbutton1 in the callback of pushbutton2. pushbutton2 does the job of converting the image to grayscale. the error that I am getting is :

Error using imread>parse_inputs (line 458)
The filename or url argument must be a string.

Error in imread (line 317)
[filename, fmt_s, extraArgs] = parse_inputs(varargin{:});

Error in simpleplan3>pushbutton2_Callback (line 96)
handles.y = rgb2gray(imread(handles.imagedata.pushbutton1));

Error in gui_mainfcn (line 96)
        feval(varargin{:});

Error in simpleplan3 (line 42)
    gui_mainfcn(gui_State, varargin{:});

Error in
@(hObject,eventdata)simpleplan3('pushbutton2_Callback',hObject,eventdata,guidata(hObject))

Error while evaluating uicontrol Callback

Answer 1

[Sven]

Hi Saurabh,

This one has a simple solution. Note the call in your first function:

handles.pushbutton1 = imread(uigetfile);

After that function is finished, the contents of handles.pushbutton1 is the image matrix itself, and not the filename to the image. Therefore in the second function where you call:

handles.y = rgb2gray(imread(handles.pushbutton1));

You can simply replace that with:

handles.y = rgb2gray(handles.pushbutton1);

Did that answer your question?

Thanks, Sven.