camera interfacing with matlab

Hi all, I'm using following code for camera interfacing with matlab.

vid = videoinput('winvideo',1,'YUY2_640x480');%Specifying video output format and size

triggerconfig(vid,'manual');%Configuring Triggering method

set(vid,'framesPerTrigger',1);

set(vid,'TriggerRepeat',Inf);

start(vid);

preview(vid);

pause(2);

set(vid,'ReturnedColorSpace','rgb');

trigger(vid);

im = getdata(vid,1);

rect = [240,320];

im = imcrop(im,rect);

imshow(im);

stop(vid);

delete(vid);

clear vid;

This code runs perfect till imshow(im) but i want the camera to stop afterwards but it's not working properly.

individually when i'm doing this procedure camera starting, snap and camera stopping it works perfect but not altogather.