Video Grab using Vision Toolbox

vid = videoinput('winvideo', 1, 'RGB24_320x240'); %select input device

hvpc = vision.VideoPlayer;   %create video player object

src = getselectedsource(vid);
vid.FramesPerTrigger =1;
vid.TriggerRepeat = Inf;
vid.ReturnedColorspace = 'rgb';
src.FrameRate = '30';
start(vid)

%start main loop for image acquisition
for t=1:500
  imgO=getdata(vid,1,'uint8');    %get image from camera
  hvpc.step(imgO);    %see current image in player
end

http://stackoverflow.com/questions/8901824/getsnapshot-speedup