   cv and grab webcam frame
  Hy .I have a problem with cg and artoolkitplus.I grab in an infinite cicle the current frame of the webcam with cv,and send it to the artoolkit function that detect the marker.image = cvQueryFrame(g_Capture);// Convert to RGBcvCvtColor(image, image, CV_BGR2RGB);The problem is that in the image struct the image->imageData (that is the raw data of the frame image) is alwais empty.Then if i send it to the :int markerId = m_tracker->calc(image->imageData ); , it dont reconize none.Why the image-A>imageData can be empty?I see in runtime that i don't move the camera the raw data becomes 0 , so if i move quik the camera the raw data is filled.Can be some procedure for save time in the webcam?thanks.   