how do i make matlab keep the camera on when i call getsnapshot?

every time i call the getsnapshot function to get an image from from the webcam... matlab restarts the webcam to get the next frame. this seems to slow down my program. :(

is there a way to keeps the camera initialized when getting the next image?

the getsnapshot function is in a loop and an annotated image is displayed.

thanks in advanced :D