jit.height?

seriously though, I think maybe you’re approaching this from the wrong angle – there is no jitter object to automatically calculate human height, you’d probably be better off going down the path of detecting (hair)colour, with very broad parameters and using that to locate people’s heads. If you are filming against a brightly-lit white wall, a lot of your work is already done.

Sound like you’re going for something like this: http://www.youtube.com/watch?v=iBVsIf1XxZ8