Matlab Gui - Adquire Video

Hello guys,

I have one app matlab gui to adquire one vídeo IP from my telephone.

When i press connect, I start transmitting the image in an 'axe' and it works fine.

But i need one function for when i press 'DISCONNECT' button, he Stop transmitting the image and clean the graphic, i try do: cla, delete, but nothing do.

Can you help me?

My code:

% --- Executes on button press in connect.
function connect_Callback(hObject, eventdata, handles)
global vid;
% hObject    handle to connect (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
vid = ipcam('http://100.75.51.93:8081/', 'admin', '12345');

while true
    [Imag_filled1, Imag_in1] = IPProcessamentoRed(vid);
    axes(handles.axes1);
    imshow(Imag_in1);
    axes(handles.axes2);
    imshow(Imag_filled1);
end    


% --- Executes on button press in disconnect.
function disconnect_Callback(hObject, eventdata, handles)
global vid;
stop(vid);
flushdata(vid);
cla(handles.axes1);
delete(vid);
clear vid 

Answer 1

[Geoff Hayes]

Sérgio - I suspect the problem might be with your while loop that is preventing the disconnect_Callback from being processed. You could try adding a brief pause to the body of the while loop so that the other function can be evaluated (but I think that you will see one or more errors when doing this since your while loop condition is always set to true and once vid becomes invalid, any call to it will result in an error.

An alternative approach might be to use a timer which you start and stop from your "connect" and "disconnect" callbacks respectively. The timer would fire periodically (at a rate to be determined by you) and its callback would acquire the video (or image) from your phone and display it in the axes.

Your code might look something like

 function connect_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)
 handles.timer = timer('Name','MyTimer',               ...
                       'Period',1,                    ... 
                       'StartDelay',1,                 ... 
                       'TasksToExecute',inf,           ... 
                       'ExecutionMode','fixedSpacing', ...
                       'TimerFcn',{@timerCallback,handles.figure1}); 
 handles.vid = ipcam('http://100.75.51.93:8081/', 'admin', '12345');
 guidata(hObject,handles);
 start(handles.timer);
 
 % --- Executes on button press in disconnect.
function disconnect_Callback(hObject, eventdata, handles)
if isfield(handles, 'vid') && isfield(handles, 'timer')
    stop(handles.timer);
    stop(handles.vid);
    flushdata(handles.vid);
    cla(handles.axes1);
    delete(handles.vid);
    handles.vid = [];
    guidata(hObject, handles);
end

 function [] = timerCallback(~,~,guiHandle)
 if ~isempty(guiHandle)
    [Imag_filled1, Imag_in1] = IPProcessamentoRed(handles.vid);
    axes(handles.axes1);
    imshow(Imag_in1);
    axes(handles.axes2);
    imshow(Imag_filled1);
 end

Note how the global variable has been removed and is stored as a field to the handles structure (along with the timer object). The abovie is untested but it might give you an idea of what you can do.