How to fix this matlab error? : I got this error when I tried to capture image using my pc webcam. I am new to matlab. How can I fix this error? 

This is my code,

    obj =imaq.VideoDevice('dcam', 1, 'YUYV_320x240','ROI', [1 1 320 240]); set(obj,'ReturnedColorSpace', 'rgb'); figure('menubar','none','tag','webcam');


>> imaqhwinfo

ans = 

    InstalledAdaptors: {'dcam'}
        MATLABVersion: '8.6 (R2015b)'
          ToolboxName: 'Image Acquisition Toolbox'
       ToolboxVersion: '4.10 (R2015b)'

>> webcamlist

ans = 

    'Integrated Webcam'



