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The emergence of online social networks (OSNs) and the accompanying availability of large amounts of data, pose a number of new natural language processing (NLP) and computational challenges. Data from OSNs is different to data from traditional sources (e.g. newswire). The texts are short, noisy and conversational. Another important issue is that data(More)
In order to analyse surveillance video, we need to efficiently explore large datasets containing videos of walking humans. At survei llance-image resolution, the human walk (their gait) can be determined automatically, and more readily than other features such as the face. Effective analysis of such data relies on retrieval of video data which has been(More)
Semantic spaces encode similarity relationships between objects as a function of position in a mathematical space. This paper discusses three different formulations for building semantic spaces which allow the automatic-annotation and semantic retrieval of images. The models discussed in this paper require that the image content be described in the form of(More)
The 2013 MediaEval Retrieving Diverse Social Images Task looked to tackling the problem of search result diversification of Flickr results sets formed from queries about geographic places and landmarks. In this paper we describe our approach of using a min-max similarity diversifier coupled with pre-filters and a reranker. We also demonstrate a number of(More)
Combining items from social media streams, such as Flickr photos and Twitter tweets, into meaningful groups can help users contextu-alise and effectively consume the torrents of information now made available on the social web. This task is made challenging due to the scale of the streams and the inherently multimodal nature of the information to be(More)
OpenIMAJ and ImageTerrier are recently released open-source libraries and tools for experimentation and development of multimedia applications using Java-compatible programming languages. OpenIMAJ (the Open toolkit for Intelligent Multimedia Analysis in Java) is a collection of libraries for multimedia analysis. The image libraries contain methods for(More)
ImageTerrier is a novel easily extensible open-source, scalable, high-performance search engine platform for content-based image retrieval applications. The platform provides a comprehensive test-bed for experimenting with bag-of-visual-words image retrieval techniques. It incorporates a state-of-the-art implementation of the single-pass indexing technique(More)
The SIFT keypoint descriptor is a powerful approach to encoding local image description using edge orientation histograms. Through codebook construction via <i>k</i>-means clustering and quantisation of SIFT features we can achieve image retrieval treating images as bags-of-words. Intensity inversion of images results in distinct SIFT features for a single(More)
There is a wide array of online photographic content that is not geotagged. Algorithms for efficient and accurate geographical estimation of an image are needed to geolocate these photos. This paper presents a general model for using both textual metadata and visual features of photos to automatically place them on a world map.