124,587 research outputs found
Unsupervised learning of a scene-specific coarse gaze estimator
No full textWe present a method to estimate the coarse gaze directions of people from surveillance data. Unlike previous work we aim to do this without recourse to a large hand-labelled corpus of training data. In contrast we propose a method for learning a classifier without any hand labelled data using only the output from an automatic tracking system. A Conditional Random Field is used to model the interactions between the head motion, walking direction, and appearance to recover the gaze directions and simultaneously train randomised decision tree classifiers. Experiments demonstrate performance exceeding that of conventionally trained classifiers on two large surveillance datasets.Ben Benfold and Ian Rei
Colour invariant head pose classification in low resolution video
No full textThis paper presents an algorithm for the classification of head pose in low resolution video. Invariance to skin, hair and background colours is achieved by classifying using an ensemble of randomised ferns which have been trained on labelled images. The ferns are used to simultaneously classify the head pose and to identify the most likely hypothesis for the mapping between colours and labels. Results from video sequences demonstrate that an improved posterior estimation using learnt colour distributions reduces classification error and provides accurate pose information in images where the head occupies as little as 10 pixels square.Ben Benfold and Ian Reidhttp://www.comp.leeds.ac.uk/bmvc2008/proceedings/index.htm
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Guiding visual surveillance by tracking human attention
No full textWe describe a novel method for directing the attention of an automated surveillance system. Our starting premise is that the attention of people in a scene can be used as an indicator of interesting areas and events. To determine people’s attention from passive visual observations we develop a system for automatic tracking and detection of individual heads to infer their gaze direction. The former is achieved by combining a histogram of oriented gradient (HOG) based head detector with frame-to-frame tracking using multiple point features to provide stable head images. The latter is achieved using a head pose classification method which uses randomised ferns with decision branches based on both HOG and colour based features to determine a coarse gaze direction for each person in the scene. By building both static and temporally varying maps of areas where people look we are able to identify interesting regions.Ben Benfold, Ian Reidhttp://www.bmva.org/bmvc/2009/index.ht
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Cognitive visual tracking and camera control
No full textAbstract not availableNicola Bellotto, Ben Benfold, Hanno Harland, Hans-Hellmut Nagel, Nicola Pirlo, Ian Reid, Eric Sommerlade, Chuan Zha
Stable multi-target tracking in real-time surveillance video
No full textThe majority of existing pedestrian trackers concentrate on maintaining the identities of targets, however systems for remote biometric analysis or activity recognition in surveillance video often require stable bounding-boxes around pedestrians rather than approximate locations. We present a multi-target tracking system that is designed specifically for the provision of stable and accurate head location estimates. By performing data association over a sliding window of frames, we are able to correct many data association errors and fill in gaps where observations are missed. The approach is multi-threaded and combines asynchronous HOG detections with simultaneous KLT tracking and Markov-Chain Monte-Carlo Data Association (MCM-CDA) to provide guaranteed real-time tracking in high definition video. Where previous approaches have used ad-hoc models for data association, we use a more principled approach based on a Minimal Description Length (MDL) objective which accurately models the affinity between observations. We demonstrate by qualitative and quantitative evaluation that the system is capable of providing precise location estimates for large crowds of pedestrians in real-time. To facilitate future performance comparisons, we make a new dataset with hand annotated ground truth head locations publicly available.Ben Benfold and Ian Reidhttp://cvpr2011.org/index.htm
Gaze directed camera control for face image acquisition
No full textFace recognition in surveillance situations usually requires high resolution face images to be captured from remote active cameras. Since the recognition accuracy is typically a function of the face direction with frontal faces more likely to lead to reliable recognition we propose a system which optimises the capturing of such images by using coarse gaze estimates from a static camera. By considering the potential information gain from observing each target, our system automatically sets the pan, tilt and zoom values (i.e. the field of view) of multiple cameras observing different tracked targets in order to maximise the likelihood of correct identification. The expected gain in information is influenced by the controllable field of view, and by the false positive and negative rates of the identification process, which are in turn a function of the gaze angle. We validate the approach using a combination of simulated situations and real tracking output to demonstrate superior performance over alternative approaches, notably using no gaze information, or using gaze inferred from direction of travel (i.e. assuming each person is always looking directly ahead).We also show results from a live implementation with a static camera and two pan-tilt-zoom devices, involving real-time tracking, processing and control.Eric Sommerlade, Ben Benfold and Ian Rei
Pragmatic Case Studies as a Source of Unity in Applied Psychology
No full textTo unify or not to unify applied psychology: that is the question. In this article we review pendulum swings in the historical efforts to answer this question—from a comprehensive, positivist, “top-down,” deductive yes between the 1930s and the early 60s, to a postmodern no since then. A rationale and proposal for a limited, “bottom-up,” inductive yes in applied psychology is then presented, employing a case-based paradigm that integrates both positivist and postmodern themes and components. This paradigm is labeled “pragmatic psychology” and, its specific use of case studies, the “Pragmatic Case Study Method” (“PCS Method”). We call for the creation of peer-reviewed journal-databases of pragmatic case studies as a foundational source of unifying applied knowledge in our discipline. As one example, the potential of the PCS Method for unifying different angles of theoretical regard is illustrated in an area of applied psychology, psychotherapy, via the case of Mrs. B. The article then turns to the broader historical and epistemological arguments for the unifying nature of the PCS Method in both applied and basic psychology.Peer reviewe
Dr. Edwin Wright Collection: Author Unknown
No full textNotes - The author relates several short stories about his neighbours including Alex McDonell, homesteading and life around Meanook and Athabasca (1 page
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