Discontinuity analysis for video processing

THESIS 821

Fork

Patent for a mechanical fork that is operated using the thumb or finger

A Multiscale Approach to Shot Change Detection

We describe a multistage approach to shot cut detection based on image descriptor differencing at a coarse temporal scale, followed by identification of shot cuts and fades at frame-level accuracy based on explicit modelling of image data evolution during fades

Exploiting temporal discontinuities for event detection and manipulation in video streams

Discontinuities in any information bearing signal serve to represent much of the vital or interesting content in that signal. A sharp loud noise in a movie could be a gun, or something breaking. In sports like tennis, cricket or snooker/pool it would indicate a point scoring event. In both cases the discontinuity is likely to be semantically relevant without further inference being necessary, once a particular domain is adopted. This paper discusses the importance of temporal motion discontinuities in inferring events in visual media. Two particular application domains are considered: content based audio/video synchronisation and event spotting in observational Psychology

Content based access for a massive database of human observation video

International audienceWe present in this paper a CBIR system for use in a psychological study of the relationship between human movement and Dyslexia. The system allows access to up to 500 hours of video and is an example of a scientific user context. This user context requires 100% accurate indexing and retrieval for a set of specific queries. This paper presents a novel use of interactive visual and audio cues for attaining this level of indexing performance. Furthermore, the issue of motion estimation accuracy in the presence of compression artifacts is explored as part of the data integrity storage problem. In addition, content based motion analysis techniques accurate enough to parse sequences on the basis of motion and objectively evaluate that motion are investigated. The tool allows Psychologists to undertake a study that would previously be impractical and the paper presents a number of lessons gained from the ongoing work

Temporal synchronization of multiple audio signals

Given the proliferation of consumer media recording de-vices, events often give rise to a large number of recordings. These recordings are taken from different spatial positions and do not have reliable timestamp information. In this pa-per, we present two robust graph-based approaches for syn-chronizing multiple audio signals. The graphs are constructed atop the over-determined system resulting from pairwise sig-nal comparison using cross-correlation of audio features. The first approach uses a Minimum Spanning Tree (MST) tech-nique, while the second uses Belief Propagation (BP) to solve the system. Both approaches can provide excellent solutions and robustness to pairwise outliers, however the MST ap-proach is much less complex than BP. In addition, an exper-imental comparison of audio features-based synchronization shows that spectral flatness outperforms the zero-crossing rate and signal energy. Index Terms — Multi-signal synchronization, audio fea-ture analysis, minimum spanning tree, belief propagation 1