Semantic indexing of images and videos by active learning.
type: Dataset
description: The general framework of this thesis is semantic indexing and information retrieval, applied to multimedia documents. More specifically, we are interested in the semantic indexing of concepts in images and videos by the active learning approaches that we use to build annotated corpus. Throughout this thesis, we have shown that the main difficulties of this task are often related, in general, to the semantic-gap. Furthermore, they are related to the class-imbalance problem in large scale datasets, where concepts are mostly sparse. For corpus annotation, the main objective of using active learning is to increase the system performance by using as few labeled samples as possible, thereby minimizing the cost of labeling data (e.g. money and time). In this thesis, we have contributed in several levels of multimedia indexing and proposed three approaches that outperform state-of-the-art systems: i) the multi-learner approach (ML) that overcomes the class-imbalance problem in large-scale datasets, ii) a re-ranking method that improves the video indexing, iii) we have evaluated the power-law normalization and the PCA and showed its effectiveness in multimedia indexing. Furthermore, we have proposed the ALML approach that combines the multi-learner with active learning, and also proposed an incremental method that speeds up ALML approach. Moreover, we have proposed the active cleaning approach, which tackles the quality of annotations. The proposed methods were validated through several experiments, which were conducted and evaluated on large-scale collections of the well-known international benchmark, called TrecVid. Finally, we have presented our real-world annotation system based on active learning, which was used to lead the annotations of the development set of TrecVid 2011 campaign, and we have presented our participation at the semantic indexing task of the mentioned campaign, in which we were ranked at the 3rd place out of 19 participants.
identifier: NNT: 2012GRENM073
issued: 2026-05-30T07:24:40.959296
language: fr
modified: 2026-05-30T07:24:40.959303
contact point: Organization
  fn: CCSD
keyword: active-learning
keyword: apprentissage-actif
keyword: indexation-multimedia
keyword: indexation-semantique
keyword: infoeu-reposemanticsdoctoralthesis
keyword: infoinfo-ohcomputer-science-csother-csoh
keyword: multimedia-indexing
keyword: semantic-indexing
keyword: theses
landing page: https://theses.hal.science/tel-00766904

Semantic indexing of images and videos by active learning.
type: Distribution
format: HTML
issued: 2026-05-30T07:24:40.978112
modified: 2026-05-30T07:24:40.932266
access URL: https://theses.hal.science/tel-00766904

test_moissonnage_selune
type: Agent