Scalable Mining of Objects and Events from Community Photo Collections

Till Quack
(ETH Zurich, Switzerland)

We describe an approach for mining images of objects (such as landmark buildings) from community photo collections in an unsupervised fashion. Our approach relies on retrieving geotagged photos from those web-sites using a grid of geospatial tiles. The downloaded photos are clustered into potentially interesting entities through a processing pipeline of several modalities, including visual, textual and spatial proximity. The resulting clusters are analyzed and are automatically classified into objects and events. Using data mining techniques, we then find text labels for these clusters, which are used to again assign each cluster to a corresponding Wikipedia article in a fully unsupervised manner. A final verification step uses the contents (including images) from the selected Wikipedia article to verify the cluster-article assignment.

We demonstrate this approach on several urban areas, densely covering an area of over 700 square kilometers and mining over 200,000 photos.