Learn More
In this paper, we propose a new type of multi-dimensional Hidden Markov Model based on the idea of Dependency Tree between positions. This simplification leads to an efficient implementation of the re-estimation algorithms, while keeping a mix of horizontal and vertical dependencies between positions. We explain DT-HMM and we present the formulas for the(More)
This paper provides an overview of the Social Event Detection (SED) task, which is organized as part of the MediaEval 2011 benchmarking activity. With the convergence between social networking and multimedia creation and distribution being experienced on a regular basis by hundreds of millions of people worldwide, this task examines how new or state of the(More)
ÐThis paper presents a new compact shape representation for retrieving line-patterns from large databases. The basic idea is to exploit both geometric attributes and structural information to construct a shape histogram. We realize this goal by computing the N-nearest neighbor graph for the lines-segments for each pattern. The edges of the neighborhood(More)
In this paper we propose to compare two region-based approaches to content-based video indexing and retrieval. Namely a comparison of a system using the Earth Mover's Distance and a system using the Latent Semantic Indexing is provided. Region-based methods allow to keep the local information in a way that reflects the human perception of the content. Thus,(More)
This paper describes a graph-matching technique for recognising line-pattern shapes in large image databases. The methodological contribution of the paper is to develop a Bayesian matching algorithm that uses edge-consistency and node attribute similarity. This information is used to determine the a posteriori probability of a query graph for each of the(More)
We present a complete and efficient framework for video shot indexing and retrieval. Video shots are described by their key-frame, themselves described by their regions. Region-based approaches suffer from the complexity of segmentation and comparison tasks. A compact region-based shot representation is usually obtained thanks to vector-quantization method.(More)
In this paper, we present our approach and results of the MediaEval 2011 social event detection (SED) task. We solve the event detection problem in three steps. First, we query all event instances that happened given some condition. Then, an event identification model is proposed to measure the relationship between events and photos. Finally, visual pruning(More)
This paper presents a novel multi-dimensional hidden Markov model approach to tackle the complex issue of image modeling. We propose a set of efficient algorithms that avoids the exponential complexity of regular multi-dimensional HMMs for the most frequent algorithms (Baum-Welch and Viterbi) due to the use of a random dependency tree (DT-HMM). We provide(More)
Low-level features are now becoming insufficient to build efficient content-based retrieval systems. The interest of users is not anymore to retrieve visually similar content, but they expect that retrieval systems find documents with similar semantic content. Bridging the gap between low-level features and semantic content is a challenging task necessary(More)