Hi
I reckon you could get the approximate sizes as long as the photo is high res and clear, the pic is straight on and you have the OD of the bars (if old school, should be a given!) with these parameters, you could get there or there abouts, might not be MM perfect though. used to have to do this sort of thing quite a bit when working for a POS company years ago.
let us know what you have.
Mark M