Image databases: a case study in Norwegian silver authentication

Establishing the identity of the craftsmen of old Norwegian silver objects can be accomplished through the recognition of master-marks. Manually searching through the 6000 master-marks and 250 city-marks is tedious and unreliable. Our-goal is to develop an efficient retrieval of images of master- and city-marks from large databases based on the shape content of the image. We are building an automatic retrieval system to browse through the entire database. The first step is to extract primitive visual features from the images and to retrieve images on the basis of these features. We have developed a prototype image database of master-marks from a catalog by scanning 171 of these marks which appear on silver tankards. We have successfully extracted shape features from these marks and matched master-marks in the database against the unknown query images. Initial experiments on master-marks are encouraging. The same shape-based matching techniques are used to match city-marks. Our future work will involve building an expert system for a stylistic analysis of the silver tankards