Topographical survey technique for examining works of art - uses scanned laser beam producing image on photographic emulsion

摘要

The topographical survey technique is particularly suitable for examining works of art. The points of impact of a rotating laser ray scanning a plane which is parallel to a photosensitive emulsion are recorded photographically on this emulsion. Onto this photograph, a second view is superimposed. This view provides an image, at a known scale, of elements placed in the plane scanned by the laser ray. The negative thus obtained is used to measure the position and the dimensions of the different elements cutting the plane scanned by the laser ray.