how to draw an updating rectangle object on a video stream ?

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Steven 2012-11-9

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Hi there,

I am beginninger of matlab. I tried myCameraGUI example which build up a simple camera preview inferface. My question is I cannot find a way to draw a updating rectangle object on the top of streamed video. I do have tried many times, but fail in the end. Does anyone know how to do that? Any direction, webpage, or even a function would be appreciated. Thank you.

Steven

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Image Analyst 2012-11-9

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It's possible to have graphics in the overlay above your live video. Did you call the preview() function to get live video, and then call plot() to plot your box?

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Image Analyst 2012-11-9

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You need two x and two y, not one. Try calling line just like this

axes(handles.cameraAxes);
hold on;
line([x1 x2], [y1 y2]);

Steven 2012-11-9

编辑：Steven 2012-11-9

Could I ask you a question further? Say I'd like to process the input video frame by frame, and base on each frame that I get from the source camera I calculate the box and then update the box that I originally ploted on the video, what is best way of doing this in terms of system performance? Could you please recommand me a few functions that could do this. thanks a lot

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