Color detection and tracking in matlab,,,,,,heeeeeeeelp?

here is the problem; i have to detect a color in a real time video (live video) from my webcam and track this color when it moves,,,i would use matlab,,but i tried with it and all tools are designed for images and recorded videos not live ones,,furthermore is there anyway to do such a task using the Simulink in matlab,,i really need help in this issue,,,,,