I want to Superimpose a picture of needle-like structures onto a real-time video? Do you know a S/W to do this?

I am trying to superimpose a CAD picture of some needle-like structures onto a real-time video of some of these misaligned needles. I shall use the CAD file to know the correct position of the needles. Do you know any software etc which will allow me to superimpose the CAD file on the real-time video?