MR VISSER
Yes.   You just mentioned that it is rather straightforward, but I gathered from page 198 of the article which you sent us, right at the top in the right-hand column, it says
"A further drawback is that the error of the positioning peg marks on the images, may be as high as two to three millimetres in all directions from the true location."
So, it does not appear from a reading of this, that it is all that straightforward, it takes some skill?