Simplifying colors and shapes from [jit.qt.grab]

Hello,

I'm new to Jitter and haven't got the best vocabulary to find out by myself, so if you help me express this it would be great:

I need to find a way to detect the most common surface--colors (this is, the averaged mix of the colors in a given surface or shape) from a live web-cam stream and pass a list with the color and its shape to anywhere else. I tried implementing [histogram] but i still miss a way to mix the colors and detect the shapes.

I know this sounds a bit abstract, and that's the problem: I don't know where to start looking... Can anyone help me/give me a hint?

Thanks for your time!