MATLAB - error:Webcam Device ID 1 is in use, hogyan kellene kijavitani a hibát?

Ezt a kodot szerettem volna kiprobalni:

[link]

de ezt a hibar irja ki:

Error using videoinput (line 391) winvideo: The device associated with device ID 1 is already in use. A new videoinput object cannot be created for this device while it is in use.

Error in trck_movng_obj (line 2) vid = videoinput('winvideo',1,'YUY2_160X120');