DWS at MediaEval 2014 Retrieving Diverse Social Images: Approaches for Visual and Textual Runs

We present an overview of our two runs submitted to the MediaEval 2014 Retrieving Diverse Social Images task, each relying only on visual and textual features. Whilst the approach for textual features is based on a standard tf-idf bag-of-words approach, we focused for visual features on a more complex contribution for the task which consists of clustering the images and diversifying the result list based on visual features. At its heart, our method relies on using images collected for each location from Wikipedia. These images are then used as centroids of clusters, where the images collected from Flickr based on their similarity to the Wikipedia images are later grouped in. Both runs, namely using either visual or textual information only, achieve precision-oriented (i.e., more than twice higher precision than recall) results.