Temporal Web Image Retrieval

International audienceTemporal Web Image Retrieval can be defined as the process that retrieves sets ofWeb images with their temporal dimension from explicit or implicit temporal text queries. Supposing that (a) the temporal dimension is included in image indexing and (b) the query is explicitly expressed with a time tag (e.g. "Fukushima 2011"), the retrieval task can be straightforward as image retrieval has been studied for several years with success. However, text queries are usually implicit in time (e.g. "Second World War") and automatically capturing the time dimension included in Web images is a challenge that has not been studied so far to the best of our knowledge. In this paper, we will discuss different research issues about Temporal Web Image Retrieval and the current progresses of our research in temporal ephemeral clustering and temporal image filtering

Time and information retrieval: Introduction to the special issue

The Special Issue of Information Processing and Management includes research papers on the intersection between time and information retrieval. In 'Evaluating Document Filtering Systems over Time', Tom Kenter and Krisztian Balog propose a time-aware way of measuring a system's performance at filtering documents. Manika Kar, SeAa7acute;rgio Nunes and Cristina Ribeiro present interesting methods for summarizing changes in dynamic text collections over time in their paper 'Summarization of Changes in Dynamic Text Collection using Latent Dirichlet Allocation Model.' Hideo Joho, Adam Jatowt and Roi Blanco report on the temporal information searching behaviour of users and their strategies for dealing with searches that have a temporal nature in 'Temporal Information Searching Behaviour and Strategies', a user study. In controlled settings, thirty participants are asked to perform searches on an array of topics on the web to find information related to particular time scopes. Adam Jatowt, Ching-man Au Yeung and Katsumi Tanaka present a 'Generic Method for Detecting Content Time of Documents'. The authors propose several methods for estimating the focus time of documents, i.e. the time a document's content refers to. Xujian Zhao, Peiquan Jin and Lihua Yue present an approach to determining the time of the underlying topic or event in their article entitled 'Discovering Topic Time from Web News'

High-Precision Photogrammetry for Glaciology

Consumer-grade digital cameras have become ubiquitous tools for documenting short-term variability in the geosciences. However, these devices were not intended for precise timekeeping and surveying, and their use as such requires management of systematic and random errors that inevitably arise.This dissertation presents a suite of methods for registering the place and time of photographs in an absolute reference frame so that they may be analyzed and interpreted alongside other spatial and temporal data. The methods are tested on a 13-year record of 33,000 time-lapse photographs from Alaska's Columbia Glacier. This work provides insights into the capabilities and shortcomings of consumer-grade cameras as scientific instruments, the opportunistic approaches often needed to achieve the best results, and the potential of continuous high-frequency measurements for documenting rapid geomorphic processes.Subsecond-precision image capture times are achieved by measuring the offset to a reference clock display and accounting for the drift, precision, and reporting resolution of the camera clock. Two case studies illustrate the benefit of subsecond precision in contemporary investigations: georeferencing aerial photogrammetric surveys with camera positions time-interpolated from GPS tracklogs, and coupling videos of glacier-calving events to synchronous seismic waveforms. Retroactive dating of photographs, on the order of seconds to hours, is achieved by leveraging phenomena visible in the photographs -- namely, the positions of astronomical objects in the sky or the corresponding variations in solar radiation and sea level.Similarly, retroactive camera calibrations are achieved using surface and topographic features in the photographs -- specifically, point and line features of known absolute position, the motion of static features in images due to camera rotation, and the correspondences between real images and images synthesized from vertical imagery. Camera motion is corrected by computing globally optimal estimates of rotation over arbitrarily-long photographic sequences.Finally, a recently-developed tracking algorithm based on particle filtering theory is refined and applied to estimate Columbia Glacier velocities, their associated uncertainties, and the corresponding strain rate fields at 3-day intervals over a 13-year period, providing an unprecedented look at the seasonal and sub-seasonal variability of tidewater glacier dynamics over long time scales

Temporal Web Image Retrieval

International audienceTemporal Web Image Retrieval can be defined as the process that retrieves sets ofWeb images with their temporal dimension from explicit or implicit temporal text queries. Supposing that (a) the temporal dimension is included in image indexing and (b) the query is explicitly expressed with a time tag (e.g. "Fukushima 2011"), the retrieval task can be straightforward as image retrieval has been studied for several years with success. However, text queries are usually implicit in time (e.g. "Second World War") and automatically capturing the time dimension included in Web images is a challenge that has not been studied so far to the best of our knowledge. In this paper, we will discuss different research issues about Temporal Web Image Retrieval and the current progresses of our research in temporal ephemeral clustering and temporal image filtering

Datation d'Images pour la Recherche Temporelle d'Information

International audienceRÉSUMÉ. Cet article s'inscrit dans le contexte de la recherche temporelle d'information qui est une thématique en plein essor depuis ces cinq dernières années. La temporalité peut être vue comme un axe de diversification permettant de raffiner les résultats des requêtes formulées par les utilisateurs. Dans cet article, nous présentons une étude sur la datation automatique de pho-tographies pour la recherche temporelle d'images de la Toile. Ce processus de datation impose de nombreuses considérations à la fois théoriques et techniques caractérisant cette tâche parti-culière. Nous essayons ici de résumer quelles sont les difficultés et les problématiques associées à ce sujet, avant de chercher à désamorcer les problèmes soulevés en proposant des solutions et des pistes de travail futures. ABSTRACT. This paper presents a new area in the domain of Temporal Information Retrieval, which has received much attention for the last few years. Temporality can be viewed as a way of diversifying Web search results in response to any given user's query. In this paper, we describe a study about image timestamping for temporal web image retrieval. This process imposes a large amount of theoretical and technical considerations that we try to summarize and evidence. Finally, we try to unlock the raised problems by proposing potential solutions and ideas for future works. MOTS-CLÉS : Recherche temporelle d'information, datation d'images, caractéristiques visuelles et textuelles, classification, régression, classes ordonnée