A Study on Visual Focus of Attention Recognition from Head Pose in a Meeting Room

This paper presents a study on the recognition of the visual focus of attention (VFOA) of meeting participants based on their head pose. Contrarily to previous studies on the topic, in our set-up, the potential VFOA of people is not restricted to other meeting participants only, but includes environmental targets (table, slide screen). This has two consequences. Firstly, this increases the number of possible ambiguities in identifying the VFOA from the head pose. Secondly, due to our particular set-up, the identification of the VFOA from head pose can not rely on an incomplete representation of the pose (the pan), but requests the knowledge of the full head pointing information (pan and tilt). In this paper, using a corpus of 8 meetings of 8 minutes on average, featuring 4 persons involved in the discussion of statements projected on a slide screen, we analyze the above issues by evaluating, through numerical performance measures, the recognition of the VFOA from head pose information obtained either using a magnetic sensor device (the ground truth) or a vision based tracking system (head pose estimates). The results clearly show that in complex but realistic situations, it is quite optimistic to believe that the recognition of the VFOA can solely be based on the head pose, as some previous studies had suggested

Exploiting the Shapley Value in the Estimation of the Position of a Point of Interest for a Group of Individuals

Concepts and tools from cooperative game theory are exploited to quantify the role played by each member of a team in estimating the position of an observed point of interest. The measure of importance known as “Shapley value” is used to this end. From the theoretical point view, we propose a specific form of the characteristic function for the class of cooperative games under investigation. In the numerical analysis, different configurations of a group of individuals are considered: all individuals looking at a mobile point of interest, one of them replaced with an artificially-generated one who looks exactly toward the point of interest, and directions of the heads replaced with randomly-generated directions. The corresponding experimental outcomes are compared

Graphical representation of meetings on mobile devices

The AMIDA Mobile Meeting Assistant is a system that allows remote participants to attend a meeting through a mobile device. The system improves the engagement in the meeting of the remote participants with respect to voice-only solutions thanks to the use of visual annotations and the capture of slides. The visual focus of attention of meeting participants and other annotations serve to reconstruct a 2D or a 3D representation of the meeting on a mobile device (smart phone). A rst version of the system has been implemented, and feedback from a user study and from industrial partners shows that the Mobile Meeting Assistant's functionalities are positively appreciated, and sets priorities for future developments

A Cognitive and Unsupervised MAP Adaptation Approach to the Recognition of the Focus of Attention from Head Pose

In this paper, the recognition of the visual focus of attention (VFOA) of meeting participants (as defined by their eye gaze direction) from their head pose is addressed. To this end, the head pose observations are modeled using an Hidden Markov Model (HMM) whose hidden states corresponds to the VFOA. The novelties are threefold. First, contrary to previous studies on the topic, in our set-up, the potential VFOA of a person is not restricted to other participants only, but includes environmental targets (a table and a projection screen), which increases the complexity of the task, with more VFOA targets spread in the pan and tilt (as well) gaze space. Second, the HMM parameters are set by exploiting results from the cognitive science on saccadic eye motion, which allows to predict what the head pose should be given an actual gaze target. Third, an unsupervised parameter adaptation step is proposed which accounts for the specific gazing behaviour of each participant. Using a publicly available corpus of 8 meetings featuring 4 persons, we analyze the above methods by evaluating, through objective performance measures, the recognition of the VFOA from head pose information obtained either using a magnetic sensor device or a vision based tracking system

Who Will Get the Grant ? A Multimodal Corpus for the Analysis of Conversational Behaviours in Group

In the last couple of years more and more multimodal corpora have been created. Recently many of these corpora have also included RGB-D sensors' data. However, there is to our knowledge no publicly available corpus, which combines accurate gaze-tracking, and high- quality audio recording for group discussions of varying dynamics. With a corpus that would fulfill these needs, it would be possible to investigate higher level constructs such as group involvement, individual engagement or rapport, which all require multi-modal feature extraction. In the following paper we describe the design and recording of such a corpus and we provide some illustrative examples of how such a corpus might be exploited in the study of group dynamics

Recognition and Understanding of Meetings The AMI and AMIDA Projects

The AMI and AMIDA projects are concerned with the recognition and interpretation of multiparty meetings. Within these projects we have: developed an infrastructure for recording meetings using multiple microphones and cameras; released a 100 hour annotated corpus of meetings; developed techniques for the recognition and interpretation of meetings based primarily on speech recognition and computer vision; and developed an evaluation framework at both component and system levels. In this paper we present an overview of these projects, with an emphasis on speech recognition and content extraction

学生の満足度に付随したヴァーチャルラーニングにおける有効性向上の創造と非言語的行動についての調査

国立大学法人長岡技術科学大

Camera-based estimation of student's attention in class

Two essential elements of classroom lecturing are the teacher and the students. This human core can easily be lost in the overwhelming list of technological supplements aimed at improving the teaching/learning experience. We start from the question of whether we can formulate a technological intervention around the human connection, and find indicators which would tell us when the teacher is not reaching the audience. Our approach is based on principles of unobtrusive measurements and social signal processing. Our assumption is that students with different levels of attention will display different non-verbal behaviour during the lecture. Inspired by information theory, we formulated a theoretical background for our assumptions around the idea of synchronization between the sender and receiver, and between several receivers focused on the same sender. Based on this foundation we present a novel set of behaviour metrics as the main contribution. By using a camera-based system to observe lectures, we recorded an extensive dataset in order to verify our assumptions. In our first study on motion, we found that differences in attention are manifested on the level of audience movement synchronization. We formulated the measure of ``motion lag'' based on the idea that attentive students would have a common behaviour pattern. For our second set of metrics we explored ways to substitute intrusive eye-tracking equipment in order to record gaze information of the entire audience. To achieve this we conducted an experiment on the relationship between head orientation and gaze direction. Based on acquired results we formulated an improved model of gaze uncertainty than the ones currently used in similar studies. In combination with improvements on head detection and pose estimation, we extracted measures of audience head and gaze behaviour from our remote recording system. From the collected data we found that synchronization between student's head orientation and teacher's motion serves as a reliable indicator of the attentiveness of students. To illustrate the predictive power of our features, a supervised-learning model was trained achieving satisfactory results at predicting student's attention

BEYOND MULTI-TARGET TRACKING: STATISTICAL PATTERN ANALYSIS OF PEOPLE AND GROUPS

Ogni giorno milioni e milioni di videocamere monitorano la vita quotidiana delle persone, registrando e collezionando una grande quantit\ue0 di dati. Questi dati possono essere molto utili per scopi di video-sorveglianza: dalla rilevazione di comportamenti anomali all'analisi del traffico urbano nelle strade. Tuttavia i dati collezionati vengono usati raramente, in quanto non \ue8 pensabile che un operatore umano riesca a esaminare manualmente e prestare attenzione a una tale quantit\ue0 di dati simultaneamente. Per questo motivo, negli ultimi anni si \ue8 verificato un incremento della richiesta di strumenti per l'analisi automatica di dati acquisiti da sistemi di video-sorveglianza in modo da estrarre informazione di pi\uf9 alto livello (per esempio, John, Sam e Anne stanno camminando in gruppo al parco giochi vicino alla stazione) a partire dai dati a disposizione che sono solitamente a basso livello e ridondati (per esempio, una sequenza di immagini). L'obiettivo principale di questa tesi \ue8 quello di proporre soluzioni e algoritmi automatici che permettono di estrarre informazione ad alto livello da una zona di interesse che viene monitorata da telecamere. Cos\uec i dati sono rappresentati in modo da essere facilmente interpretabili e analizzabili da qualsiasi persona. In particolare, questo lavoro \ue8 focalizzato sull'analisi di persone e i loro comportamenti sociali collettivi. Il titolo della tesi, beyond multi-target tracking, evidenzia lo scopo del lavoro: tutti i metodi proposti in questa tesi che si andranno ad analizzare hanno come comune denominatore il target tracking. Inoltre andremo oltre le tecniche standard per arrivare a una rappresentazione del dato a pi\uf9 alto livello. Per prima cosa, analizzeremo il problema del target tracking in quanto \ue8 alle basi di questo lavoro. In pratica, target tracking significa stimare la posizione di ogni oggetto di interesse in un immagine e la sua traiettoria nel tempo. Analizzeremo il problema da due prospettive complementari: 1) il punto di vista ingegneristico, dove l'obiettivo \ue8 quello di creare algoritmi che ottengono i risultati migliori per il problema in esame. 2) Il punto di vista della neuroscienza: motivati dalle teorie che cercano di spiegare il funzionamento del sistema percettivo umano, proporremo in modello attenzionale per tracking e il riconoscimento di oggetti e persone. Il secondo problema che andremo a esplorare sar\ue0 l'estensione del tracking alla situazione dove pi\uf9 telecamere sono disponibili. L'obiettivo \ue8 quello di mantenere un identificatore univoco per ogni persona nell'intera rete di telecamere. In altre parole, si vuole riconoscere gli individui che vengono monitorati in posizioni e telecamere diverse considerando un database di candidati. Tale problema \ue8 chiamato in letteratura re-indetificazione di persone. In questa tesi, proporremo un modello standard di come affrontare il problema. In questo modello, presenteremo dei nuovi descrittori di aspetto degli individui, in quanto giocano un ruolo importante allo scopo di ottenere i risultati migliori. Infine raggiungeremo il livello pi\uf9 alto di rappresentazione dei dati che viene affrontato in questa tesi, che \ue8 l'analisi di interazioni sociali tra persone. In particolare, ci focalizzeremo in un tipo specifico di interazione: il raggruppamento di persone. Proporremo dei metodi di visione computazionale che sfruttano nozioni di psicologia sociale per rilevare gruppi di persone. Inoltre, analizzeremo due modelli probabilistici che affrontano il problema di tracking (congiunto) di gruppi e individui.Every day millions and millions of surveillance cameras monitor the world, recording and collecting huge amount of data. The collected data can be extremely useful: from the behavior analysis to prevent unpleasant events, to the analysis of the traffic. However, these valuable data is seldom used, because of the amount of information that the human operator has to manually attend and examine. It would be like looking for a needle in the haystack. The automatic analysis of data is becoming mandatory for extracting summarized high-level information (e.g., John, Sam and Anne are walking together in group at the playground near the station) from the available redundant low-level data (e.g., an image sequence). The main goal of this thesis is to propose solutions and automatic algorithms that perform high-level analysis of a camera-monitored environment. In this way, the data are summarized in a high-level representation for a better understanding. In particular, this work is focused on the analysis of moving people and their collective behaviors. The title of the thesis, beyond multi-target tracking, mirrors the purpose of the work: we will propose methods that have the target tracking as common denominator, and go beyond the standard techniques in order to provide a high-level description of the data. First, we investigate the target tracking problem as it is the basis of all the next work. Target tracking estimates the position of each target in the image and its trajectory over time. We analyze the problem from two complementary perspectives: 1) the engineering point of view, where we deal with problem in order to obtain the best results in terms of accuracy and performance. 2) The neuroscience point of view, where we propose an attentional model for tracking and recognition of objects and people, motivated by theories of the human perceptual system. Second, target tracking is extended to the camera network case, where the goal is to keep a unique identifier for each person in the whole network, i.e., to perform person re-identification. The goal is to recognize individuals in diverse locations over different non-overlapping camera views or also the same camera, considering a large set of candidates. In this context, we propose a pipeline and appearance-based descriptors that enable us to define in a proper way the problem and to reach the-state-of-the-art results. Finally, the higher level of description investigated in this thesis is the analysis (discovery and tracking) of social interaction between people. In particular, we focus on finding small groups of people. We introduce methods that embed notions of social psychology into computer vision algorithms. Then, we extend the detection of social interaction over time, proposing novel probabilistic models that deal with (joint) individual-group tracking