AVA: A Video Dataset of Spatio-temporally Localized Atomic Visual Actions

This paper introduces a video dataset of spatio-temporally localized Atomic Visual Actions (AVA). The AVA dataset densely annotates 80 atomic visual actions in 430 15-minute video clips, where actions are localized in space and time, resulting in 1.58M action labels with multiple labels per person occurring frequently. The key characteristics of our dataset are: (1) the definition of atomic visual actions, rather than composite actions; (2) precise spatio-temporal annotations with possibly multiple annotations for each person; (3) exhaustive annotation of these atomic actions over 15-minute video clips; (4) people temporally linked across consecutive segments; and (5) using movies to gather a varied set of action representations. This departs from existing datasets for spatio-temporal action recognition, which typically provide sparse annotations for composite actions in short video clips. We will release the dataset publicly. AVA, with its realistic scene and action complexity, exposes the intrinsic difficulty of action recognition. To benchmark this, we present a novel approach for action localization that builds upon the current state-of-the-art methods, and demonstrates better performance on JHMDB and UCF101-24 categories. While setting a new state of the art on existing datasets, the overall results on AVA are low at 15.6% mAP, underscoring the need for developing new approaches for video understanding.Comment: To appear in CVPR 2018. Check dataset page https://research.google.com/ava/ for detail

Beyond multimedia adaptation: Quality of experience-aware multi-sensorial media delivery

Multiple sensorial media (mulsemedia) combines multiple media elements which engage three or more of human senses, and as most other media content, requires support for delivery over the existing networks. This paper proposes an adaptive mulsemedia framework (ADAMS) for delivering scalable video and sensorial data to users. Unlike existing two-dimensional joint source-channel adaptation solutions for video streaming, the ADAMS framework includes three joint adaptation dimensions: video source, sensorial source, and network optimization. Using an MPEG-7 description scheme, ADAMS recommends the integration of multiple sensorial effects (i.e., haptic, olfaction, air motion, etc.) as metadata into multimedia streams. ADAMS design includes both coarse- and fine-grained adaptation modules on the server side: mulsemedia flow adaptation and packet priority scheduling. Feedback from subjective quality evaluation and network conditions is used to develop the two modules. Subjective evaluation investigated users' enjoyment levels when exposed to mulsemedia and multimedia sequences, respectively and to study users' preference levels of some sensorial effects in the context of mulsemedia sequences with video components at different quality levels. Results of the subjective study inform guidelines for an adaptive strategy that selects the optimal combination for video segments and sensorial data for a given bandwidth constraint and user requirement. User perceptual tests show how ADAMS outperforms existing multimedia delivery solutions in terms of both user perceived quality and user enjoyment during adaptive streaming of various mulsemedia content. In doing so, it highlights the case for tailored, adaptive mulsemedia delivery over traditional multimedia adaptive transport mechanisms

MUVTIME: a Multivariate time series visualizer for behavioral science

As behavioral science becomes progressively more data driven, the need is increasing for appropriate tools for visual exploration and analysis of large datasets, often formed by multivariate time series. This paper describes MUVTIME, a multimodal time series visualization tool, developed in Matlab that allows a user to load a time series collection (a multivariate time series dataset) and an associated video. The user can plot several time series on MUVTIME and use one of them to do brushing on the displayed data, i.e. select a time range dynamically and have it updated on the display. The tool also features a categorical visualization of two binary time series that works as a high-level descriptor of the coordination between two interacting partners. The paper reports the successful use of MUVTIME under the scope of project TURNTAKE, which was intended to contribute to the improvement of human-robot interaction systems by studying turn- taking dynamics (role interchange) in parent-child dyads during joint action.Marie Curie International Incoming Fellowship PIIF-GA-2011- 301155; Portuguese Foundation for Science and Technology (FCT) project PTDC/PSI- PCO/121494/2010; AFP was also partially funded by the FCT project (IF/00217/2013)This research was supported by: Marie Curie International Incoming Fellowship PIIF-GA-2011301155; Portuguese Foundation for Science and Technology (FCT) Strategic program FCT UID/EEA/00066/2013; FCT project PTDC/PSIPCO/121494/2010. AFP was also partially funded by the FCT project (IF/00217/2013). REFERENCE

An Outlook into the Future of Egocentric Vision

What will the future be? We wonder! In this survey, we explore the gap between current research in egocentric vision and the ever-anticipated future, where wearable computing, with outward facing cameras and digital overlays, is expected to be integrated in our every day lives. To understand this gap, the article starts by envisaging the future through character-based stories, showcasing through examples the limitations of current technology. We then provide a mapping between this future and previously defined research tasks. For each task, we survey its seminal works, current state-of-the-art methodologies and available datasets, then reflect on shortcomings that limit its applicability to future research. Note that this survey focuses on software models for egocentric vision, independent of any specific hardware. The paper concludes with recommendations for areas of immediate explorations so as to unlock our path to the future always-on, personalised and life-enhancing egocentric vision.Comment: We invite comments, suggestions and corrections here: https://openreview.net/forum?id=V3974SUk1

The crowd as a cameraman : on-stage display of crowdsourced mobile video at large-scale events

Recording videos with smartphones at large-scale events such as concerts and festivals is very common nowadays. These videos register the atmosphere of the event as it is experienced by the crowd and offer a perspective that is hard to capture by the professional cameras installed throughout the venue. In this article, we present a framework to collect videos from smartphones in the public and blend these into a mosaic that can be readily mixed with professional camera footage and shown on displays during the event. The video upload is prioritized by matching requests of the event director with video metadata, while taking into account the available wireless network capacity. The proposed framework's main novelty is its scalability, supporting the real-time transmission, processing and display of videos recorded by hundreds of simultaneous users in ultra-dense Wi-Fi environments, as well as its proven integration in commercial production environments. The framework has been extensively validated in a controlled lab setting with up to 1 000 clients as well as in a field trial where 1 183 videos were collected from 135 participants recruited from an audience of 8 050 people. 90 % of those videos were uploaded within 6.8 minutes

Place and Object Recognition for Real-time Visual Mapping

Este trabajo aborda dos de las principales dificultades presentes en los sistemas actuales de localización y creación de mapas de forma simultánea (del inglés Simultaneous Localization And Mapping, SLAM): el reconocimiento de lugares ya visitados para cerrar bucles en la trajectoria y crear mapas precisos, y el reconocimiento de objetos para enriquecer los mapas con estructuras de alto nivel y mejorar la interación entre robots y personas. En SLAM visual, las características que se extraen de las imágenes de una secuencia de vídeo se van acumulando con el tiempo, haciendo más laboriosos dos de los aspectos de la detección de bucles: la eliminación de los bucles incorrectos que se detectan entre lugares que tienen una apariencia muy similar, y conseguir un tiempo de ejecución bajo y factible en trayectorias largas. En este trabajo proponemos una técnica basada en vocabularios visuales y en bolsas de palabras para detectar bucles de manera robusta y eficiente, centrándonos en dos ideas principales: 1) aprovechar el origen secuencial de las imágenes de vídeo, y 2) hacer que todo el proceso pueda funcionar a frecuencia de vídeo. Para beneficiarnos del origen secuencial de las imágenes, presentamos una métrica de similaridad normalizada para medir el parecido entre imágenes e incrementar la distintividad de las detecciones correctas. A su vez, agrupamos los emparejamientos de imágenes candidatas a ser bucle para evitar que éstas compitan cuando realmente fueron tomadas desde el mismo lugar. Finalmente, incorporamos una restricción temporal para comprobar la coherencia entre detecciones consecutivas. La eficiencia se logra utilizando índices inversos y directos y características binarias. Un índice inverso acelera la comparación entre imágenes de lugares, y un índice directo, el cálculo de correspondencias de puntos entre éstas. Por primera vez, en este trabajo se han utilizado características binarias para detectar bucles, dando lugar a una solución viable incluso hasta para decenas de miles de imágenes. Los bucles se verifican comprobando la coherencia de la geometría de las escenas emparejadas. Para ello utilizamos varios métodos robustos que funcionan tanto con una como con múltiples cámaras. Presentamos resultados competitivos y sin falsos positivos en distintas secuencias, con imágenes adquiridas tanto a alta como a baja frecuencia, con cámaras frontales y laterales, y utilizando el mismo vocabulario y la misma configuración. Con descriptores binarios, el sistema completo requiere 22 milisegundos por imagen en una secuencia de 26.300 imágenes, resultando un orden de magnitud más rápido que otras técnicas actuales. Se puede utilizar un algoritmo similar al de reconocimiento de lugares para resolver el reconocimiento de objetos en SLAM visual. Detectar objetos en este contexto es particularmente complicado debido a que las distintas ubicaciones, posiciones y tamaños en los que se puede ver un objeto en una imagen son potencialmente infinitos, por lo que suelen ser difíciles de distinguir. Además, esta complejidad se multiplica cuando la comparación ha de hacerse contra varios objetos 3D. Nuestro esfuerzo en este trabajo está orientado a: 1) construir el primer sistema de SLAM visual que puede colocar objectos 3D reales en el mapa, y 2) abordar los problemas de escalabilidad resultantes al tratar con múltiples objetos y vistas de éstos. En este trabajo, presentamos el primer sistema de SLAM monocular que reconoce objetos 3D, los inserta en el mapa y refina su posición en el espacio 3D a medida que el mapa se va construyendo, incluso cuando los objetos dejan de estar en el campo de visión de la cámara. Esto se logra en tiempo real con modelos de objetos compuestos por información tridimensional y múltiples imágenes representando varios puntos de vista del objeto. Después nos centramos en la escalabilidad de la etapa del reconocimiento de los objetos 3D. Presentamos una técnica rápida para segmentar imágenes en regiones de interés para detectar objetos pequeños o lejanos. Tras ello, proponemos sustituir el modelo de objetos de vistas independientes por un modelado con una única bolsa de palabras de características binarias asociadas a puntos 3D. Creamos también una base de datos que incorpora índices inversos y directos para aprovechar sus ventajas a la hora de recuperar rápidamente tanto objetos candidatos a ser detectados como correspondencias de puntos, tal y como hacían en el caso de la detección de bucles. Los resultados experimentales muestran que nuestro sistema funciona en tiempo real en un entorno de escritorio con cámara en mano y en una habitación con una cámara montada sobre un robot autónomo. Las mejoras en el proceso de reconocimiento obtienen resultados satisfactorios, sin detecciones erróneas y con un tiempo de ejecución medio de 28 milisegundos por imagen con una base de datos de 20 objetos 3D

Geospatial Information Research: State of the Art, Case Studies and Future Perspectives

Geospatial information science (GI science) is concerned with the development and application of geodetic and information science methods for modeling, acquiring, sharing, managing, exploring, analyzing, synthesizing, visualizing, and evaluating data on spatio-temporal phenomena related to the Earth. As an interdisciplinary scientific discipline, it focuses on developing and adapting information technologies to understand processes on the Earth and human-place interactions, to detect and predict trends and patterns in the observed data, and to support decision making. The authors – members of DGK, the Geoinformatics division, as part of the Committee on Geodesy of the Bavarian Academy of Sciences and Humanities, representing geodetic research and university teaching in Germany – have prepared this paper as a means to point out future research questions and directions in geospatial information science. For the different facets of geospatial information science, the state of art is presented and underlined with mostly own case studies. The paper thus illustrates which contributions the German GI community makes and which research perspectives arise in geospatial information science. The paper further demonstrates that GI science, with its expertise in data acquisition and interpretation, information modeling and management, integration, decision support, visualization, and dissemination, can help solve many of the grand challenges facing society today and in the future

Asynchronous Ultrasonic Trilateration for Indoor Positioning of Mobile Phones

Spatial awareness is fast becoming the key feature on today‟s mobile devices. While accurate outdoor navigation has been widely available for some time through Global Positioning Systems (GPS), accurate indoor positioning is still largely an unsolved problem. One major reason for this is that GPS and other Global Navigation Satellite Systems (GNSS) systems offer accuracy of a scale far different to that required for effective indoor navigation. Indoor positioning is also hindered by poor GPS signal quality, a major issue when developing dedicated indoor locationing systems. In addition, many indoor systems use specialized hardware to calculate accurate device position, as readily available wireless protocols have so far not delivered sufficient levels of accuracy. This research aims to investigate how the mobile phone‟s innate ability to produce sound (notably ultrasound) can be utilised to deliver more accurate indoor positioning than current methods. Experimental work covers limitations of mobile phone speakers in regard to generation of high frequencies, propagation patternsof ultrasound and their impact on maximum range, and asynchronous trilateration. This is followed by accuracy and reliability tests of an ultrasound positioning system prototype.This thesis proposes a new method of positioning a mobile phone indoors with accuracy substantially better than other contemporary positioning systems available on off-theshelf mobile devices. Given that smartphones can be programmed to correctly estimate direction, this research outlines a potentially significant advance towards a practical platform for indoor Location Based Services. Also a novel asynchronous trilateration algorithm is proposed that eliminates the need for synchronisation between the mobile device and the positioning infrastructure