Any idea how this picture was made? Was the Goldstone dish scanning a really tightly focused beam across the region of space where this asteroid was, or are the

Any idea how this picture was made? Was the Goldstone dish scanning a really tightly focused beam across the region of space where this asteroid was, or are they relying on some kind of doppler or synthetic aperture radar effect with the relative movement of the dish (on a rotating Earth) and the asteroid let the image be recovered out of Doppler and timing info? I went looking for some details on how the picture was produced on the NASA page linked at the bottom of the article but I can't find much technical info on the process. However it was done I'm sure it's a cool technique!