My current approach is using self-define-computePlot function, which is still slightly slower than preview function which is directly showing the video live. Any better suggestion?
hImage = imagesc(app.UIAxes, getsnapshot(app.CamVid));
set(app.CamVid, 'TimerFcn', {@SelfDefine-computePlotFunc, hImage}, 'TimerPeriod', 0.2,'FramesPerTrigger',Inf);
start(app.CamVid);