Close Video Preview window
closepreview(obj) stops the image acquisition object
obj from previewing and, if the default Video Preview window was used,
closes the window.
closepreview stops all image acquisition objects from previewing
and, for all image acquisition objects that used the default Video Preview window, closes
Note that if the preview window was created with a user-specified image object handle as
closepreview does not close the figure window.
Introduced before R2006a