A method for ascertaining the position of an edge in or on an object surface region of interest by optical scanning. The reflectivity of the object surface region is evaluated. Light is emitted onto the object surface region under different illumination conditions, in particular different light incidence directions, and in each illumination condition a sequence S1 to Sn of camera images B is recorded. Each camera image B of a sequence S1 to Sn is recorded at another illumination intensity I. Subsequently in each case one reflectivity image R1 to Rn is produced from a plurality of or from all camera images B of a sequence S1 to Sn. Thereafter, a resulting reflectivity image E is produced from a plurality of or from all reflectivity images R1 to Rn by weighted addition, in which resulting reflectivity image E the position of an edge is determined.