How to best set up an App to aquire a live video feed and process its data

Hi,

I'am tasked with creating a standalone app in Matlab R2022b to collect the video stream and process the data/analyze it. The app is supposed to run for extended periods of time.

I want to base the main part around a switch. Is this a viable solution? Meaning if the switch is turned on, I want to do some setup task and then enter a loop that keeps on repeating. If the switch is turned off by the user, the loop should end and some code to finsish off the calculations should be done in the end too. If the switch is toggled again, the system should be able to restart.

When I tried similar things to this before, the app would freeze up. It would not respond to the toggle button changing.

So is this about the right way to adress such a task, or should I handle it differently? Is there a way to keep the rest of the app responsive, while this loop is executed?

Thank you for your help!

      % Value changed function: Switch_on_off
        function Switch_on_offValueChanged(app, event)

            if app.Switch_on_off.Value == 1
                  % do preperations

            else
                %do clean up

            end
           
            while app.Switch_on_off.Value == 1

                    % do preperations

                    %check for job request

                    if job_available == 1

                            % repeated process for duration of job:
                            while job_ongoing == true
                                       
                                   %grab video frame and update viewer in
                                   %App

                                   %do image processing
                                   %temporary store results

                                   if app.Switch_on_off.Value == 0 %end loop if toggled
                                       break
                                   end
                               
                            end
                            try
                            % return results to API
                            end
                    else
                        %grab video frame and update viewer in APP
                    end



            end
            
        end
    end

Answer 1

[Oliver Jaehrig]

You need to use Parallel Computing to make apps responsive. It currently sounds like you are not using parallel computing features, do you?

I recommend to check this documentation page and examples so you can see what I mean:

https://www.mathworks.com/help/matlab/matlab_prog/use-the-background-to-make-your-apps-more-responsive.html

[Sebastian]

Yes in my test I was not using the parallel computing features.

I will look into it!

Thank you for your help!