Étude sur l’influence du vocabulaire utilisé pour l’indexation des images en contexte de repérage multilingue

During the last few years, the Internet has become an indispensable medium for the dissemination of multilingual resources. However, language differences are often a major obstacle to the exchange of scientific, cultural, educational and commercial documents. Besides this linguistic diversity, many databases and collections now contain documents in various formats that can also adversely affect their retrieval process. In general, images are considered to be language-independent resources. Nevertheless, the image indexing process using either a controlled or uncontrolled vocabulary gives the image a linguistic status similar to any other textual document and thus leads to the same difficulties in their retrieval. The goal of our research is to first identify the differences between the indexing approaches using a controlled and an uncontrolled vocabulary for ordinary images of everyday-life objects and to then differentiate between the results obtained at the time of image retrieval. This study supposes that the two indexing approaches show not only common characteristics, but also differences that can influence image retrieval. Thus, this research makes it possible to indicate if one of these indexing approaches surpasses the other in terms of effectiveness, efficiency, and satisfaction of the image searcher in a multilingual retrieval context. For this study, two specific objectives are defined: to identify the characteristics of each approach used for ordinary image indexing of everyday-life objects that can effect image retrieval in a multilingual context; and to explore the differences between the two indexing approaches in terms of their effectiveness, their efficiency, and the satisfaction of the image searcher when trying to retrieve ordinary images of everyday-life objects indexed according to either approach in a multilingual retrieval context. Three methods of data collection are used: an analysis of the image indexing terms, a simulation of the retrieval of a set of images indexed according to each of the two indexing approaches conducted with sixty respondents, and a questionnaire submitted to the participants during and after the retrieval simulation. Four measures are defined in this research: the effectiveness of image retrieval measured by the success rate calculated in terms of the number of retrieved images; time efficiency measured by the average time, in seconds, used to retrieve an image; human efficiency measured in terms of the human effort represented per average number of queries necessary to retrieve an image; and the satisfaction of the image searcher measured by the self-evaluation of the participant of the retrieval process after each completed task. This research shows that in terms of ordinary image indexing representing everyday-life objects, the two approaches investigated are fundamentally distinct on the terminological, perceptual, and structural perspective. Additionally, the analysis of the characteristics of the two indexing approaches reveals that if the indexing language differs, the characteristics vary little within the same indexing approach. Finally, this research underlines that the two indexing approaches of ordinary images representing everyday-life objects have a retrieval performance that is different in terms of its effectiveness, efficiency, and satisfaction of the image searcher according to the approach and the language used for indexing.

Keyphrases: RIML, Image indexing, Image retrieval, Controlled vocabulary, Uncontrolled vocabulary, Cross-language information retrieval, CLIR, Evaluation, Machine translation, Ordinary image, Information organization, Information representation, Usability