We present an investigation of sharing the focus of visual attention between two players in a collaborative game, so that where one player was looking was visible to the other. The difference between using head-gaze and eye-gaze to estimate the point of regard was studied, the motive being that recording head-gaze is easier and cheaper than eye-gaze. Two experiments are reported, the first investigates the effect of a high immersion presentation of the game in VR Head Mounted Display compared with a lower immersion desktop presentation. The second examines the high immersion condition in more detail. The studies show that in spite of there being many factors that could affect the outcome of a relatively short period of game play, sharing eye-gaze in the high immersion condition produces shorter overall durations and better subjective ratings of team work than does sharing head-gaze. This difference is not apparent in the low immersion condition. The findings are a good argument for exploiting the opportunities for including and using eye tracking within head mounted displays in the context of collaborative games.

Collaboration improves efficiency, avoids duplication of efforts, improves goal-awareness, and makes working generally more pleasurable. While collaboration is desirable, it introduces additional costs because of the required coordination. In this article, we study how visual search is affected by gaze-sharing collaboration. There is evidence that pairs of visual searchers using gaze-only sharing are more efficient than single searchers. We extend this result by investigating if groups of three searchers are more efficient, and if and how the groups of searchers develop their search strategy. We conducted an experiment to understand how the collaboration develops when groups of one to three participants perform a visual search task by collaborating with shared gaze. The task was to state if the target was present among distractors. Our results show that users are able to develop an efficient search and division-of-labor strategy when the only collaboration method is gaze-sharing.

To use eye trackers in a school classroom, children need to be able to calibrate their own tracker unsupervised and on repeated occasions. A game designed specifically around the need to maintain their gaze in fixed locations was used to collect calibration and verification data. The data quality obtained was compared with a standard calibration procedure and another game, in two studies carried out in three elementary schools. One studied the effect on data quality over repeated occasions and the other studied the effect of age on data quality. The first showed that accuracy obtained from unsupervised calibration by children was twice as good after six occasions with the game requiring the fixed gaze location compared with the standard calibration, and as good as standard calibration by group of supervised adults. In the second study, age was found to have no effect on performance in the groups of children studied.

Gaze gestures are deliberate patterns of eye movements that can be used to invoke commands. These are less reliant on accurate measurement and calibration than other gaze-based interaction techniques. These may be used with wearable displays fitted with eye tracking capability, or as part of an assistive technology. The visual stimuli in the information on the display that can act as fixation targets may or may not be sparse and will vary over time. The paper describes an experiment to investigate how the amount of information provided on a display to assist making fixations affects gaze gesture performance. The impact of providing visualization guides and small fixation targets on the time to complete gestures and error rates is presented. The number and durations of fixations made during gesture completion is used to explain differences in performance as a result of practice and direction of eye movement.

We aim to identify the salient objects in an image by applying a model of visual attention. We automate the process by predicting those objects in an image that are most likely to be the focus of someone's visual attention. Concretely, we first generate fixation maps from the eye tracking data, which express the ground truth of people's visual attention for each training image. Then, we extract the high-level features based on the bag-of-visual-words image representation as input attributes along with the fixation maps to train a support vector regression model. With this model, we can predict a new query image's saliency. Our experiments show that the model is capable of providing a good estimate for human visual attention in test images sets with one salient object and multiple salient objects. In this way, we seek to reduce the redundant information within the scene, and thus provide a more accurate depiction of the scene.

Traditionally, devices which are able to determine a users gaze are large, expensive and often restrictive. We investigate the prospect of using common webcams and mobile devices such as laptops, tablets and phones without modification as an alternative means for obtaining a users gaze. A person's gaze can be fundamentally determined by the pose of the head as well as the orientation of the eyes. This initial work investigates the first of these factors - an estimate of the 3D head pose (and subsequently the positions of the eye centres) relative to a camera device. Specifically, we seek a low cost algorithm that requires only a one-time calibration for an individual user, that can run in real-time on the aforementioned mobile devices with noisy camera data. We use our head tracker to estimate the 4 eye corners of a user over a 10 second video. We present the results at several different frames per second (fps) to analyse the impact on the tracker with lower quality cameras. We show that our algorithm is efficient enough to run at 75fps on a common laptop, but struggles with tracking loss when the fps is lower than 10fps.

The two cardinal problems recognized with gaze-based interaction techniques are: how to avoid unintentional commands, and how to overcome the limited accuracy of eye tracking. Gaze gestures are a relatively new technique for giving commands, which has the potential to overcome these problems. We present a study that compares gaze gestures with dwell selection as an interaction technique. The study involved 12 participants and was performed in the context of using an actual application. The participants gave commands to a 3D immersive game using gaze gestures and dwell icons. We found that gaze gestures are not only a feasible means of issuing commands in the course of game play, but they also exhibited performance that was at least as good as or better than dwell selections. The gesture condition produced less than half of the errors when compared with the dwell condition. The study shows that gestures provide a robust alternative to dwell-based interaction with the reliance on positional accuracy being substantially reduced.

Gaze-based interaction techniques have been investigated for the last two decades, and in many cases the evaluation of these has been based on trials with able-bodied users and conventional usability criteria, mainly speed and accuracy. The target user group of many of the gaze-based techniques investigated is, however, people with different types of physical disabilities. We present the outcomes of two studies that compare the performance of two groups of participants with a type of physical disability (one being cerebral palsy and the other muscular dystrophy) with that of a control group of able-bodied participants doing a task using a particular gaze interaction technique. One study used a task based on dwell-time selection, and the other used a task based on gaze gestures. In both studies, the groups of participants with physical disabilities performed significantly worse than the able-bodied control participants. We question the ecological validity of research into gaze interaction intended for people with physical disabilities that only uses able-bodied participants in evaluation studies without any testing using members of the target user population.

To enable people with motor impairments to use gaze control to play online games and take part in virtual communities, new interaction techniques are needed that overcome the limitations of dwell clicking on icons in the games interface. We have investigated gaze gestures as a means of achieving this. We report the results of an experiment with 24 participants that examined performance differences between different gestures. We were able to predict the effect on performance of the numbers of legs in the gesture and the primary direction of eye movement in a gesture. We also report the outcomes of user trials in which 12 experienced gamers used the gaze gesture interface to play World of Warcraft. All participants were able to move around and engage other characters in fighting episodes successfully. Gestures were good for issuing specific commands such as spell casting, and less good for continuous control of movement compared with other gaze interaction techniques we have developed.

This paper proposes a simple approach to an old problem, that of the 'Midas Touch'. This uses modes to enable different types of mouse behavior to be emulated with gaze and by using gestures to switch between these modes. A light weight gesture is also used to switch gaze control off when it is not needed, thereby removing a major cause of the problem. The ideas have been trialed in Second Life, which is characterized by a feature-rich of set of interaction techniques and a 3D graphical world. The use of gaze with this type of virtual community is of great relevance to severely disabled people as it can enable them to be in the community on a similar basis to able-bodied participants. The assumption here though is that this group will use gaze as a single modality and that dwell will be an important selection technique. The Midas Touch Problem needs to be considered in the context of fast dwell-based interaction. The solution proposed here, Snap Clutch, is incorporated into the mouse emulator software. The user trials reported here show this to be a very promising way in dealing with some of the interaction problems that users of these complex interfaces face when using gaze by dwell.

Throughout the history of gaze tracking, there have been several dimensions along which the evolution of gaze-based communication can be viewed. Perhaps the most important of these dimensions is the ease of use, or usability, of systems incorporating eye tracking. Usable communication through eye-gaze has been a goal for many years and offers the prospect of effortless and fast communication for able bodied and disabled users alike. To date such communication has been hampered by a number of problems limiting its widespread uptake. Systems have evolved over time and can provide effective means of communication within restricted bounds, but these are typically incompatible and limited to a few application areas, and each has suffered from particular usability problems. As a consequence uptake remains low and the cost of individual eyetracking systems remains high. However, more is being understood and published about the usability requirements for eye-gaze communication systems, particularly for users with different types of disability. With the advance of research and technology we are now seeing genuinely usable systems which can be used for a broad range of applications and, with this, the prospect of much wider acceptance of gaze as a means of communication.A second dimension is how we can utilise our communication through eye gaze. Much work has been undertaken addressing the nature of control and the concepts of active and passive control, or command-based and non-command based interaction. Active control and the giving of commands by eye to on-screen keyboards and other control interfaces is now well known and has lead to greatly improved usability via compensation for the limitations of eyetrackers as a data source, and by providing predictive and corrective capabilities to the user interface. Passive monitoring of gaze position leads to the notion of gaze-aware objects which are capable of responding to user attention in a way appropriate to the specific task context. Early work by Starker and Bolt [1990], for example, assigned objects in a virtual world gaze based indices of interest where control was mediated by system evaluation of user interest without the need for active user control. By employing these concepts current gaze control systems have now achieved acceptable ease of use by making on-screen objects gaze-aware, allowing compensation for tracking and manipulation inaccuracies. Gaze aware interaction is now migrating from the confines of the desktop to the user task space in the real world within a ubiquitous computing context. Instead of attempting to track gaze position in world space relative to the user, with the many difficulties this presents in inaccuracies and encumbering equipment, gaze tracking can be moved to many ubiquitous objects in the real world. Visual contact and manipulation with gaze aware instrumented objects is now possible by equipping objects with eye-contact sensors detecting infra-red corneal reflection from users looking at these objects. Alternatively, objects can be equipped with infra-red emitters and the detection of the corneal reflection of these can be moved to low-cost head-mounted cameras worn by the user. These two approaches to visual contact detection parallel desk-mounted and head-mounted eye-tracking systems.In the future, we can expect very real benefits from gaze-based communication in a wider set of task domains as ubiquitous systems become more able to make informed decisions about the intent of a user. Such systems will finally liberate eye gaze communication from the confines of laboratory and desktop, to the real world, enabling low-cost communication through gaze to be available for all.This paper gratefully acknowledges the support of the COGAIN Communication by Gaze Interaction European Commission Fp6 Network of Excellence project.

This paper quantifies the benefits and usability problems associated with eye-based pointing direct interaction on a standard graphical user interface. It shows where and how, with the addition of a second supporting modality, the typically poor performance and subjective assessment of eye-based pointing devices can be improved to match the performance of other assistive technology devices. It shows that target size is the overriding factor affecting device performance and that when target sizes are artificially increased by 'zooming in' on the interface under the control of a supporting modality then eye-based pointing becomes a viable and usable interaction methodology for people with high-level motor disabilities.