Biometric responses to music-rich segments in films: the CDVPlex

Summarising or generating trailers for films or movies involves finding the highlights within those films, those segments where we become most afraid, happy, sad, annoyed, excited, etc. In this paper we explore three questions related to automatic detection of film highlights by measuring the physiological responses of viewers of those films. Firstly, whether emotional highlights can be detected through viewer biometrics, secondly whether individuals watching a film in a group experience similar emotional reactions as others in the group and thirdly whether the presence of music in a film correlates with the occurrence of emotional highlights. We analyse the results of an experiment known as the CDVPlex, where we monitored and recorded physiological reactions from people as they viewed films in a controlled cinema-like environment. A selection of films were manually annotated for the locations of their emotive contents. We then studied the physiological peaks identified among participants while viewing the same film and how these correlated with emotion tags and with music. We conclude that these are highly correlated and that music-rich segments of a film do act as a catalyst in stimulating viewer response, though we don't know what exact emotions the viewers were experiencing. The results of this work could impact the way in which we index movie content on PVRs for example, paying special significance to movie segments which are most likely to be highlights

Mind the Gap: Another look at the problem of the semantic gap in image retrieval

This paper attempts to review and characterise the problem of the semantic gap in image retrieval and the attempts being made to bridge it. In particular, we draw from our own experience in user queries, automatic annotation and ontological techniques. The first section of the paper describes a characterisation of the semantic gap as a hierarchy between the raw media and full semantic understanding of the media's content. The second section discusses real users' queries with respect to the semantic gap. The final sections of the paper describe our own experience in attempting to bridge the semantic gap. In particular we discuss our work on auto-annotation and semantic-space models of image retrieval in order to bridge the gap from the bottom up, and the use of ontologies, which capture more semantics than keyword object labels alone, as a technique for bridging the gap from the top down

Saliency for Image Description and Retrieval

We live in a world where we are surrounded by ever increasing numbers of images. More often than not, these images have very little metadata by which they can be indexed and searched. In order to avoid information overload, techniques need to be developed to enable these image collections to be searched by their content. Much of the previous work on image retrieval has used global features such as colour and texture to describe the content of the image. However, these global features are insufficient to accurately describe the image content when different parts of the image have different characteristics. This thesis initially discusses how this problem can be circumvented by using salient interest regions to select the areas of the image that are most interesting and generate local descriptors to describe the image characteristics in that region. The thesis discusses a number of different saliency detectors that are suitable for robust retrieval purposes and performs a comparison between a number of these region detectors. The thesis then discusses how salient regions can be used for image retrieval using a number of techniques, but most importantly, two techniques inspired from the field of textual information retrieval. Using these robust retrieval techniques, a new paradigm in image retrieval is discussed, whereby the retrieval takes place on a mobile device using a query image captured by a built-in camera. This paradigm is demonstrated in the context of an art gallery, in which the device can be used to find more information about particular images. The final chapter of the thesis discusses some approaches to bridging the semantic gap in image retrieval. The chapter explores ways in which un-annotated image collections can be searched by keyword. Two techniques are discussed; the first explicitly attempts to automatically annotate the un-annotated images so that the automatically applied annotations can be used for searching. The second approach does not try to explicitly annotate images, but rather, through the use of linear algebra, it attempts to create a semantic space in which images and keywords are positioned such that images are close to the keywords that represent them within the space