Losing frames when "getdata"

In a simple user interface I want to include a capture the image from my camera. To do this I have two push button. A start button to start acquiring the live image and a stop button to stop acquiring the image.

The basic problem is that I get the error:

GETDATA timed out before FRAMES were available.

And this is because I interrupt the TimerFcn of the vid. How can I tackle this?

Here is what I do:

function mycam

S.fh = figure('units','pixels',...
              'position',[300 300 400 400],...
              'menubar','none',...
              'name','stopwatch',...
              'numbertitle','off');

S.pb(1) = uicontrol('style','push',...
                    'units','pixels',...
                    'position',[10 10 85 30],...
                    'fontsize',14,...
                    'string','start',...
                    'CallBack',@switchon);
S.pb(2) = uicontrol('style','push',...
                    'units','pixels',...
                    'position',[105 10 85 30],...
                    'fonts',14,...
                    'str','stop',...
                    'Callback',@switchoff);

NumberFrameDisplayPerSecond=20;

vid=videoinput('winvideo',1);
set(vid, 'timerFcn',@updater,...
          'TimerPeriod', 1/NumberFrameDisplayPerSecond,...
         'FramesPerTrigger',1,...
         'TriggerRepeat',Inf);
triggerconfig(vid, 'Manual');

      function updater(varargin)
          persistent stream
          trigger(vid);
          IM=getdata(vid,1,'uint8');
          if isempty(stream)
              stream = imshow(IM);
          else
              set(stream, 'CData', IM)
          end
      end
      function switchon(varargin)
          start(vid)
      end
      function switchoff(varargin)
          stop(vid)
      end 
  end

Thank you

[Ramu Pradip]

I have the same problem as well. Any tips ?

Answer 1

[Walter Roberson]

Perhaps wait() on the timer after you stop() it.

[Giorgos Papakonstantinou]

Thank you Walter, but who is going to wait for what?

[Giorgos Papakonstantinou]

I added |flushdata | in my switchoff callback. However, the problem persists. I think that the actual problem lies on the fact I am calling other functions while the timer is executing.

Therefore, I the interruption of the timer is causing the problems. How can I interrupt the timer?

Apart from that I cannot do much while I try to debug my code.

function switchoff(varargin)
        flushdata(vid);
        stop(vid)
  end

Thank you