Ancient Roman Coin Retrieval: A Systematic Examination of the Effects of Coin Grade

Ancient coins are historical artefacts of great significance which attract the interest of scholars, and a large and growing number of amateur collectors. Computer vision based analysis and retrieval of ancient coins holds much promise in this realm, and has been the subject of an increasing amount of research. The present work is in great part motivated by the lack of systematic evaluation of the existing methods in the context of coin grade which is one of the key challenges both to humans and automatic methods. We describe a series of methods - some being adopted from previous work and others as extensions thereof - and perform the first thorough analysis to date.