Question Regarding MATLAB GUI, a problem while playing back a live video.

Greetings programmers,

I have completed my codes for live video streaming and wanted to move into GUI to make it look nicer. The problem I have encountered is that when I put my codes into my Start Button Callback function, Matlab always opens another window to show me the video instead of inside the created Axel when I was creating the GUI. Previously I have created a GUI using image processing which uses this function: preview() to show vide insides of axel.

In this coding, my final output is a step(OriginalVideo, FinalProcessed). How do I make it in such a way that my video will stay inside the axel instead of a separate window?

Thank you very much.

Regards,

Akira

[Walter Roberson]

Please show the code you use in your Start Button Callback, along with the code you use to play the video.

[Akira Chan]

Dear Mr Walter,

function Start_Callback(hObject, eventdata, handles)
  % hObject    handle to Start (see GCBO)
  % eventdata  reserved - to be defined in a future version of MATLAB
  % handles    structure with handles and user data (see GUIDATA)

    LiveVideo = imaq.VideoDevice('winvideo', 1, 'MJPG_640x480');
    vidInfo = imaqhwinfo(LiveVideo);
    VideoOut = vision.VideoPlayer('Name', 'Live Video Testing', ... 
                                'Position', [50 10 vidInfo.MaxWidth+45                                       vidInfo.MaxHeight+65]);

while (nFrames < 200)

       <Preprocessing Algorithms are here, Fill is the final output of              pre-processed image and VideoOut is my Video>

       step(VideoOut, Fill);

end

I think I should not use step function here, I need something else maybe?

Thank you very much.

Regards,

Akira

Answer 1

[Walter Roberson]

vision.VideoPlayer() appears to always create a new Figure to display the content in. It cannot be configured to display the video in an axes.

To play video in an axis, see the example http://www.mathworks.com/help/vision/examples/video-display-in-a-custom-user-interface.html

Unfortunately the key routine for that, showFrameOnAxis() is example code that I do not have access to so I do not know how it works.

[Akira Chan]

Dear Mr Walter,

Oh, thank you very much sir. I try that now.

Regards,

Akira

[Akira Chan]

Dear Mr Walter,

You are totally right, I need to use showframeonaxis, but now I have encountered a problem, it only show me a blank axes when I start my system. Nevertheless, I will create a question thread so people will know what to do when come to this problem.

Thank you very much.

Regards,

Akira