Two holes are made in a corner of sheet metal using a machine press. The tolerancing of its position is important as the holes are used for mounting the element. The holes are quite often out of the tolerance because of imprecise positioning of the item in the press.
In order to check the quality of the item, a robust machine vision is developed. The operator, after making the holes, must put the item into a slit in the vision system. An image is taken and the diameter and position of the holes is measured against the datum edges.
The image shows the specification of the holes and the contrastive image of an object with measurement overlay.
An important phase of development is the analysis of the geometrical product specification. Imaging system and processing algorithms must match the dimensions and datums as specified by the constructor.