| On the ease and efficiency of human-computer interfaces | | BIBA | Full-Text | 9-10 | |
| Shumin Zhai | |||
| Ease and efficiency are two critical qualities of human-computer interfaces. In this address, I will first examine various contributing factors to these two qualities, including recognition and recall, open and closed loop control, controlled and automatic process [Schneider and Shiffrin, 1977; Shiffrin and Schneider, 1977; Schneider and Chein, 2003], mapping directness [Hutchins et al., 1985], unit of operation, and chunking. | |||
| Longitudinal evaluation of discrete consecutive gaze gestures for text entry | | BIBAK | Full-Text | 11-18 | |
| Jacob O. Wobbrock; James Rubinstein; Michael W. Sawyer; Andrew T. Duchowski | |||
| Eye-typing performance results are reported from controlled studies
comparing an on-screen keyboard and Eye Write, a new on-screen gestural input
alternative. Results from the first pilot study suggest the presence of a
learning curve that novice users must overcome in order to gain proficiency in
EyeWrite's use (requiring practice with its letter-like gestural alphabet).
Results from the second longitudinal study indicate that EyeWrite's inherent
multi-saccade handicap (4.52 saccades per character, frequency-weighted
average) is sufficient for the on-screen keyboard to edge out Eye Write in
speed performance. Eye-typing speeds with Eye Write approach 5 wpm on average
(8 wpm attainable by proficient users), whereas keyboard users achieve about 7
wpm on average (in line with previous results). However, Eye Write users leave
significantly fewer uncorrected errors in the final text, with no significant
difference in the number of errors corrected during entry, indicating a
speed-accuracy trade-off. Subjective results indicate that participants
consider Eye Write significantly faster, easier to use, and prone to cause less
ocular fatigue than the on-screen keyboard. In addition, Eye-Write consumes
much less screen real-estate than an on-screen keyboard, giving it practical
advantages for eye-based text entry. Keywords: eye-typing, gestures, text entry, text input | |||
| Now Dasher! Dash away!: longitudinal study of fast text entry by Eye Gaze | | BIBAK | Full-Text | 19-26 | |
| Outi Tuisku; Päivi Majaranta; Poika Isokoski; Kari-Jouko Räihä | |||
| Dasher is one of the best known inventions in the area of text entry in
recent years. It can be used with many input devices, but studies on user
performance with it are still scarce. We ran a longitudinal study where 12
participants transcribed Finnish text with Dasher in ten 15-minute sessions
using a Tobii 1750 eye tracker as a pointing device. The mean text entry rate
was 2.5 wpm during the first session and 17.3 wpm during the tenth session. Our
results show that very high text entry rates can be achieved with eye-operated
Dasher, but only after several hours of training. Keywords: eye tracking, gaze writing, longitudinal study, text entry | |||
| Eye-S: a full-screen input modality for pure eye-based communication | | BIBAK | Full-Text | 27-34 | |
| Marco Porta; Matteo Turina | |||
| To date, several eye input methods have been developed, which, however, are
usually designed for specific purposes (e.g. typing) and require dedicated
graphical interfaces. In this paper we present Eye-S, a system that allows
general input to be provided to the computer through a pure eye-based approach.
Thanks to the "eye graffiti" communication style adopted, the technique can be
used both for writing and for generating other kinds of commands. In Eye-S,
letters and general eye gestures are created through sequences of fixations on
nine areas of the screen, which we call hotspots. Being usually not visible,
such sensitive regions do not interfere with other applications, that can
therefore exploit all the available display space. Keywords: alternative communication, assistive technology, eye gesture, eye sequence,
eye typing, eye writing, gaze interaction | |||
| Measurement of eye velocity using active illumination | | BIBAK | Full-Text | 35-38 | |
| Jeffrey B. Mulligan | |||
| With speeds measured in hundreds of degrees per second, measurement of
saccadic velocities can be a challenging problem, usually solved by the
application of high-frame-rate cameras or high-bandwidth analog systems. This
paper describes a novel approach utilizing a standard NTSC video camera coupled
with an array of near-infrared light-emitting diodes that are flashed at
various times within a single frame. The principle has been demonstrated with a
prototype apparatus consisting of 4 16-cell linear arrays ("light sticks"). The
cells of each light stick are energized sequentially during each video field,
while a camera captures their images reflected in the cornea. When the eye is
still, the four line segments are aligned with the vertical and horizontal
directions, but when the eye is in motion they appear tilted. Opposite light
sticks are cycled in opposite directions, producing opposite tilts. Thus, the
measurement of velocity is transformed to a measurement of the angle between
two line segments. Preliminary results from a prototype system show a noise
level of approximately 20 deg/sec. Keywords: active illumination, saccades, saccadic velocity | |||
| A method to study visual attention aspects of collaboration: eye-tracking pair programmers simultaneously | | BIBAK | Full-Text | 39-42 | |
| Sami Pietinen; Roman Bednarik; Tatiana Glotova; Vesa Tenhunen; Markku Tukiainen | |||
| The previous research of visual attention has mostly considered the
situations in which a single person performs a task. The current eye-tracking
devices and software support this research situation. Applications of
eye-tracking in the research of collaborative tasks have been rare to date. We
present a methodological framework of a research in which visual attention of
pair programmers with a single display has been studied. We discuss the
challenges of such research when conducted in real-world settings and the
requirements on the eye-tracking setups. The hardware setups and software
solutions to the problems of acquisition and synchronization of streams of
eye-tracking data are presented. We outline the methodological questions of
future visual attention research of collaborative tasks. Keywords: empirical research methodology, eye-tracking, pair programming | |||
| Testing for statistically significant differences between groups of scan patterns | | BIBAK | Full-Text | 43-46 | |
| Matt Feusner; Brian Lukoff | |||
| Pairwise sequence alignment methods are now often used when analyzing
eyetracking data [Hacisalihzade et al. 1992; Brandt and Stark 1997; Josephson
and Holmes 2002, 2006; Pan et al. 2004; Heminghous and Duchowski 2006]. While
optimal sequence alignment scores provide a valuation of similarity and
difference, they do not readily provide a statistical test of similarity or
difference. Furthermore, pairwise alignment scores cannot be used to compare
groups of scan patterns directly. Using a statistic that compiles these
pairwise alignment scores, a statistical evaluation of similarity can be made
by repeatedly computing scores from different permutations of scan pattern
groupings. This test produces a p-value as a level of statistical significance. Keywords: analysis, comparison, eye tracking, scan pattern, scanpath, sequence
comparison, similarity test, statistics | |||
| Improving hands-free menu selection using eyegaze glances and fixations | | BIBAK | Full-Text | 47-50 | |
| Geoffrey Tien; M. Stella Atkins | |||
| A real-time eyegaze selection interface was implemented using a Tobii
eyegaze tracking monitor. A hierarchical button menu was displayed on the
screen and specified selections were made by eyegaze fixations and glances on
the menu widgets. The initial version tested three different spatial layouts of
the menu widgets and employed a dwell + glance method of selection. Results
from the pilot interface led to usability improvements in the second version of
the interface. Selections were activated using a glance + dwell method. The
usability of the second study interface received a positive response from all 8
participants. Each selection gained more than a 100% speed increase using the
revised interface.
A more intuitive selection interface in the second study allowed us to test users selection accuracy at faster dwell selection thresholds. Users quickly learned to achieve accurate selections in 180 ms, but made errors when selections occurred in 150 ms. Keywords: eye pointing, eye tracking, hands free, pointing and selection, surgery | |||
| Gazing with pEYEs: towards a universal input for various applications | | BIBAK | Full-Text | 51-54 | |
| Anke Huckauf; Mario H. Urbina | |||
| Various interfaces for gaze control (which are recommended due to certain
requirements of controlling a machine by gaze) have already been developed. One
problem, especially for novice users, is that respective interfaces all look
different and require different steps to use. As a means to unify interfaces
for gaze control, pie menus are suggested. Such pEYEs allow for universal input
in various applications usable by novices and by experts. We present two
examples for pEYE interfaces; one eye-typing application and one desktop
navigation. Observations in user studies indicate effective and efficient
performance and a large acceptance. Keywords: evaluation methodology, eye-typing, gaze control, input devices, user
interfaces | |||
| Eye typing using word and letter prediction and a fixation algorithm | | BIBAK | Full-Text | 55-58 | |
| I. Scott MacKenzie; Xuang Zhang | |||
| Two eye typing techniques and a fixation algorithm are described. Similar to
word prediction, letter prediction chooses three highly probable next letters
and highlights them on an onscreen keyboard. Letter prediction proved
promising, as it was as good as word prediction, and in some cases better. The
fixation algorithm chooses which button to select for eye-over highlighting. It
often chooses the desired button even if another button is closer to the
fixation location. Error rates were reduced when using the fixation algorithm
combined with letter prediction; however, the algorithm was sensitive to the
correctness of the first several letters in a word. Keywords: button size, eye tracking, eye typing, fixation algorithm, letter
prediction, word prediction | |||
| 3D point-of-gaze estimation on a volumetric display | | BIBA | Full-Text | 59 | |
| Craig Hennessey; Peter Lawrence | |||
| Eye-gaze tracking devices are typically used to estimate the point-of-gaze (POG) of a subject on a 2D surface such as a computer screen. Using model based methods for POG estimation we have developed a system based on the vergence of the eyes which can be used to estimate the POG on a real-world volumetric display. | |||
| Limbus/pupil switching for wearable eye tracking under variable lighting conditions | | BIBAK | Full-Text | 61-64 | |
| Wayne J. Ryan; Andrew T. Duchowski; Stan T. Birchfield | |||
| We present a low-cost wearable eye tracker built from off-the-shelf
components. Based on the open source openEyes project (the only other similar
effort that we are aware of), our eye tracker operates in the visible spectrum
and variable lighting conditions. The novelty of our approach rests in
automatically switching between tracking the pupil/iris boundary in bright
light to tracking the iris/sclera boundary (limbus) in dim light. Additional
improvements include a semi-automatic procedure for calibrating the eye and
scene cameras, as well as an automatic procedure for initializing the location
of the pupil in the first image frame. The system is accurate to two degrees
visual angle in both indoor and outdoor environments. Keywords: limbus tracking, wearable eye tracking | |||
| Improving the accuracy of gaze input for interaction | | BIBAK | Full-Text | 65-68 | |
| Manu Kumar; Jeff Klingner; Rohan Puranik; Terry Winograd; Andreas Paepcke | |||
| Using gaze information as a form of input poses challenges based on the
nature of eye movements and how we humans use our eyes in conjunction with
other motor actions. In this paper, we present three techniques for improving
the use of gaze as a form of input. We first present a saccade detection and
smoothing algorithm that works on real-time streaming gaze information. We then
present a study which explores some of the timing issues of using gaze in
conjunction with a trigger (key press or other motor action) and propose a
solution for resolving these issues. Finally, we present the concept of Focus
Points, which makes it easier for users to focus their gaze when using
gaze-based interaction techniques. Though these techniques were developed for
improving the performance of gaze-based pointing, their use is applicable in
general to using gaze as a practical form of input. Keywords: eye tracking, eye-hand coordination, fixation smoothing, focus points, gaze
input, gaze-enhanced user interface design | |||
| Measuring the task-evoked pupillary response with a remote eye tracker | | BIBAK | Full-Text | 69-72 | |
| Jeff Klingner; Rakshit Kumar; Pat Hanrahan | |||
| The pupil-measuring capability of video eye trackers can detect the
task-evoked pupillary response: subtle changes in pupil size which indicate
cognitive load. We performed several experiments to measure cognitive load
using a remote video eye tracker, which demonstrate two extensions to current
research in this area. First, we show that cognitive pupillometry can be
extended from head-mounted to remote eye tracking systems. Second, we
demonstrate the feasibility of a more fine-grained approach to analyzing pupil
size data gathered with an eye tracker, which provides more detail about the
timing and magnitude of changes in cognitive load. Keywords: cognitive load, eye tracking, pupil, pupillometry, remote eye tracking,
task-evoked pupillary response | |||
| Estimation of certainty for multiple choice tasks using features of eye-movements | | BIBAK | Full-Text | 73-76 | |
| Minoru Nakayama; Yosiyuki Takahasi | |||
| To determine the performance of estimating the degree of "strength of
belief" (SOB) of responses using eye-movements, the features of eye-movements
were extracted while subjects answered questions and reviewed their own
responses to multiple choice tasks. The estimation was conducted using Support
Vector Machines (SVM) with features of eye-movements between two successive
fixations. In the results, the overall estimation performances were significant
when the prediction was calculated using certain combinations of features for
answering and reviewing sessions respectively. In comparing feature
combinations of eye-movements for significant estimations between answering and
reviewing sessions, significant combinations components of features between the
two sessions did not coincide. Keywords: certainty, estimation, eye-movements, support vector machines | |||
| Assessing usability with eye-movement frequency analysis | | BIBA | Full-Text | 77 | |
| Minoru Nakayama; Makoto Katsukura | |||
| Eye-movements can be an index of usability, though there is no significant relationship between a subjective usability score and indices of eye-movements, however [Nakayama and Katsukura 2007]. A possible reasons for this is the shortness of the observational duration. As another approach, power spectrum density (PSD) and cross spectrum density (CSD) of eye-movements can be used as an index of mental workload [Nakayama and Shimizu 2004]. This paper addresses the possibility of assessing usability using frequency analysis of eye-movements. | |||
| Integrated speech and gaze control for realistic desktop environments | | BIBAK | Full-Text | 79-82 | |
| Emiliano Castellina; Fulvio Corno; Paolo Pellegrino | |||
| Nowadays various are the situations in which people need to interact with a
Personal Computer without having the possibility to use traditional pointing
devices, such as a keyboard or a mouse. In the latest years, various
alternatives to the classical input devices like keyboard and mouse and novel
interaction paradigms have been proposed. Particularly, multimodal interactions
have been proposed to overcome the limit of each input channel take alone. In
this paper we propose a multimodal system based on the integration of speech-
and gaze-based inputs for interaction with a real desktop environment. A
real-time grammar is generated to limit the vocal vocabulary basing on the
fixated area. A disambiguation method is used for inherently ambiguous vocal
commands, and the performed tests show its efficiency. Keywords: eye tracking, multimodal interaction, speech recognition, usability | |||
| Comparing behavioural and self-report measures of engagement with an embodied conversational agent: a first report on eye tracking in Second Life | | BIBAK | Full-Text | 83-85 | |
| Sara Dalzel-Job; Craig Nicol; Jon Oberlander | |||
| Embodied Conversational Agents (ECAs) are widely used to assist users in
carrying out tasks. There are various reasons for including them in interfaces;
they may help guide a user's attention to important information; they may
improve overall task performance; or they may simply make the interface more
attractive, thereby increasing the user's motivation to engage with a task. Keywords: Second Life, embodied conversational agents, eye tracking | |||
| A head-mounted sensor-based eye tracking device: eye touch system | | BIBAK | Full-Text | 87-90 | |
| Cihan Topal; Ömer Nezih Gerek; A Atakan Doǧan | |||
| In this study, a new eye tracking system, namely Eye Touch, is introduced.
Eye Touch is based on an eyeglasses-like apparatus on which IrDA sensitive
sensors and IrDA light sources are mounted. Using inexpensive sensors and light
sources instead of a camera leads to lower system cost and need for the
computation power. A prototype of the proposed system is developed and tested
to show its capabilities. Based on the test results obtained, Eye Touch is
proved to be a promising human-computer interface system. Keywords: IrDA sensors, data acquisition, eye tracking, human-computer interface | |||
| Evaluating requirements for gaze-based interaction in a see-through head mounted display | | BIBAK | Full-Text | 91-94 | |
| Sven-Thomas Graupner; Michael Heubner; Sebastian Pannasch; Boris M. Velichkovsky | |||
| This study suggests an approach to the evaluation of gaze-based interaction
with information displayed on a see-through HMD. For these purposes, a mock-up
system consisting of a head-mounted eye tracker and a see-through HMD was
developed. In a series of three experiments subjects performed a simple point
selection task using gaze control. Various design issues were addressed
throughout including the size of interactive elements, their position on the
screen, temporal and spatial resolution parameters of the eye tracker as well
as algorithms used to enhance data quality. Reaction time and hit rate were
measured as objective indicators of performance. Keywords: eye tracking, gaze control, head-mounted displays, human computer
interaction | |||
| One-point calibration gaze tracking based on eyeball kinematics using stereo cameras | | BIBAK | Full-Text | 95-98 | |
| Takashi Nagamatsu; Junzo Kamahara; Takumi Iko; Naoki Tanaka | |||
| This paper presents a one-point calibration gaze tracking method based on
eyeball kinematics using stereo cameras. By using two cameras and two light
sources, the optic axis of the eye can be estimated. One-point calibration is
required to estimate the angle of the visual axis from the optic axis. The
eyeball rotates with optic and visual axes based on the eyeball kinematics
(Listing's law). Therefore, we introduced eyeball kinematics to the one-point
calibration process in order to properly estimate the visual axis. The
prototype system was developed and it was found that the accuracy was under
1° around the center and bottom of the display. Keywords: calibration, eye tracking, eye-ball kinematics, stereo camera | |||
| Temporal eye-tracking data: evolution of debugging strategies with multiple representations | | BIBA | Full-Text | 99-102 | |
| Roman Bednarik; Markku Tukiainen | |||
| The challenges in empirical eye-tracking studies of usability or complex
problem solving include 1) how to effectively analyze the eye-tracking data,
and 2) how to interpret and relate the resulting measures to the user cognitive
processing. We conducted a reanalysis of eye-tracking data from a recent study
that involved programmers of two experience groups debugging a program with the
help of multiple representations. The proportional fixation time on each area
of interest (AOI), frequency of visual attention switches between the areas,
and the type of switch were investigated during five consequential phases of
ten minutes of debugging. We increased the granularity of the focus on the user
processing several times, allowing us to construct a better picture of the
process. In addition, plotting the areas of interest in time supported a visual
analysis and comparison with the quantitative data.
We found repetitive patterns of visual attention that were associated with less experience in programming and lower performance. We also discovered that at the beginning of the process programmers made use of both the code and visualization while frequently switching between them. At a later stage of debugging, more experienced programmers began to increasingly integrate also the output of the program and employed a high-frequency of visual attention switching to coordinate the three representations. | |||
| EyeSecret: an inexpensive but high performance auto-calibration eye tracker | | BIBAK | Full-Text | 103-106 | |
| Zhang Yun; Zhao Xin-Bo; Zhao Rong-Chun; Zhou Yuan; Zou Xiao-Chun | |||
| With the aim to provide an inexpensive but high performance real-time head
mounted eye tracker, named EyeSecret, we present a novel system derived from
openEyes which share the common idea to integrated Eye tracker to everyday life
and reach its full potential. To obtain the robustness, intrusiveness and
accuracy from relative low-cost and off-the-shelf components, we developed the
system by parallel hardware and software design. We employed reverse
engineering and the rapid prototyping design and manufacturing as a measurement
of head gear designing; moreover, two sets of auto-calibration plans were
introduced to automatically acquire the coordinates of calibration markers in
real scene, and we also improved infrared (IR) source and implemented laser to
get qualified image and facilitates the eye tracker. Our system can reliably
estimate eye position with normal head motion indoors or outdoors and reach an
accuracy of approximately 1° visual angle, ±30° horizontal FOV
(Field of View) and ±25° vertical FOV. Keywords: auto-calibration, eye-tracking, head gear, rapid prototyping design and
manufacturing | |||
| KiEV: a tool for visualization of reading and writing processes in translation of text | | BIBAK | Full-Text | 107-110 | |
| Oleg Spakov; Kari-Jouko Räihä | |||
| The increase in usage of eye-tracking technology to study text translation
processes has revealed the need for effective tools for visualization of the
data collected. We propose a new method for gaze and keystroke data
visualization. The visualization utilizes the preprocessed gaze data, where
detected fixations are linked to the corresponding word in the text. The blocks
of reading and typing processes are shown in parallel with details for each
word presented in word bars. Reading or typing sequences provide insight into
the temporal distribution of the subject's activity, and highlighting pops up
the unusual or attention-requiring data and events. Keywords: eye tracking, gaze and keystroke data visualization, gaze data analysis,
gaze-to-word mapping, translation analysis | |||
| The incomplete fixation measure | | BIBAK | Full-Text | 111-114 | |
| Frederick Shic; Brian Scassellati; Katarzyna Chawarska | |||
| In this paper we evaluate several of the most popular algorithms for
segmenting fixations from saccades by testing these algorithms on the scanning
patterns of toddlers. We show that by changing the parameters of these
algorithms we change the reported fixation durations in a systematic fashion.
However, we also show how choices in analysis can lead to very different
interpretations of the same eye-tracking data. Methods for reconciling the
disparate results of different algorithms as well as suggestions for the use of
fixation identification algorithms in analysis, are presented. Keywords: Lévy flight, dispersion, dwell, eye-tracking, fixation
identification, mean fixation | |||
| Voluntary pupil size change as control in eyes only interaction | | BIBAK | Full-Text | 115-118 | |
| Inger Ekman; Antti Poikola; Meeri Mäkäräinen; Tapio Takala; Perttu Hämäläinen | |||
| We investigate consciously controlled pupil size as an input modality. Pupil
size is affected by various processes, e.g., physical activation, strong
emotional experiences and cognitive effort. Our hypothesis is that given
continuous feedback, users can learn to control pupil size via physical and
psychological self-regulation. We test it by measuring the magnitude of self
evoked pupil size changes following seven different instructions, while
providing real time graphical feedback on pupil size. Results show that some
types of voluntary effort affect pupil size on a statistically significant
level. A second controlled experiment confirms that subjects can produce pupil
dilation and construction on demand during paced tasks. Applications and
limitations to using voluntary pupil size manipulation as an input modality are
discussed. Keywords: affective computing, eye tracking, input modality, pupil size,
unconventional computer human interfaces | |||
| Contact-analog information representation in an automotive head-up display | | BIBAK | Full-Text | 119-122 | |
| T. Poitschke; M. Ablassmeier; G. Rigoll; S. Bardins; S. Kohlbecher; E. Schneider | |||
| This contribution presents an approach for representing contact-analog
information in an automotive Head-Up Display (HUD). Therefore, we will firstly
introduce our approach for the calibration of the optical system consisting of
the virtual image plane of the HUD and the drivers eyes. Afterward, we will
present the used eyetracking system for adaptation of the HUD content at the
current viewpoint/position of the driver. We will also present first
prototypical concepts for the visualization of contact-analog HUD content and
initial test results from a brief usability study. Keywords: HUD, automotive, calibration, contact-analog, eye tracking, head-up display | |||
| Effects of time pressure and text complexity on translators' fixations | | BIBAK | Full-Text | 123-126 | |
| Selina Sharmin; Oleg Spakov; Kari-Jouko Räihä; Arnt Lykke Jakobsen | |||
| We tracked the eye movements of 18 students as they translated three short
texts with different complexity levels under three different time constraints.
Participants with touch typing skills were found to attend more to on-screen
text than participants without touch typing skills. Time pressure was found to
mainly affect fixations on the source text, and text complexity was found to
only affect the number of fixations on the source text. Overall, it was found
that average fixation duration was longer in the target text area than in the
source text area. Keywords: eye tracking, fixation count, fixation duration, text complexity, time
pressure, translation | |||
| Real-time simulation of visual defects with gaze-contingent display | | BIBAK | Full-Text | 127-130 | |
| Margarita Vinnikov; Robert S. Allison; Dominik Swierad | |||
| Effective management and treatment of glaucoma and other visual diseases
depend on early diagnosis. However, early symptoms of glaucoma often go
unnoticed until a significant portion of the visual field is lost. The ability
to simulate the visual consequences of the disease offers potential benefits
for patients and clinical education as well as for public awareness of its
signs and symptoms. Experiments using simulated visual field defects could
identify changes in behaviour, for example during driving, that one uses to
compensate at the early stages of the disease's development. Furthermore, by
understanding how visual field defects affect performance of visual tasks, we
can help develop new strategies to cope with other devastating diseases such as
macular degeneration. A Gaze-Contingent Display (GCD) system was developed to
simulate an arbitrary visual field in a virtual environment. The system can
estimate real-time gaze direction and eye position in earth-fixed coordinates
during relatively large head movement, and thus it can be used in immersive
projection based VE systems like the CAVE™. Arbitrary visual fields are
simulated via OpenGL and Shading Language capabilities and techniques that are
supported by the GPU, thus enabling fast performance in real time. In order to
simulate realistic visual defects, the system performs multiple image
processing operations including change in acuity, brightness, color, glare and
image distortion. The final component of the system simulates different virtual
scenes that the participant can navigate through and explore. As a result, this
system creates an experimental environment to study the effects of low vision
on everyday tasks such as driving and navigation. Keywords: eye disease, foveated imaging, gaze contingent display, head-eye tracking
system, image processing, low vision, variable resolution image, visual fields | |||
| Comparison of eye movements in searching for easy-to-find and hard-to-find information in a hierarchically organized information structure | | BIBAK | Full-Text | 131-134 | |
| Yoshiko Habuchi; Muneo Kitajima; Haruhiko Takeuchi | |||
| Finding information by successively selecting hyperlinks on web pages is a
typical task performed on websites. A number of web usability studies have
provided important insights about how web visitors carry out a search, and have
concluded that "following information scent" is the fundamental process
involved in the behavior. The purpose of this paper is to explore the
relationship between the strength of information scent and web visitors'eye
movements. Four web page types with different usability problems were
considered. In an eyetracking experiment, eleven participants were asked to
find an article on a simulated encyclopedia website by first selecting a
heading from among nine provided headings, then selecting the appropriate topic
link under the selected heading. The number of eye fixations, the duration of
the fixations, and the task completion times were analyzed. The eye-tracking
study reported in this paper added further insight to the knowledge gained from
traditional web usability studies, in which visitors'performance are measured
by the total number of clicks and task completion times. Website
visitors'performance will not exhibit any differences in the initial heading
selection stage irrespective of whether or not the pages have usability
problems. However, performance will deteriorate in terms of the total number of
fixations in the subsequent link selection stage when the web page has any kind
of usability problem. Keywords: LSA, hierarchical information structure, information scent, latent semantic
analysis, web usability | |||
| Calibration-free eye tracking by reconstruction of the pupil ellipse in 3D space | | BIBAK | Full-Text | 135-138 | |
| Stefan Kohlbecher; Stanislavs Bardinst; Klaus Bartl; Erich Schneider; Tony Poitschke; Markus Ablassmeier | |||
| Most video-based eye trackers require a calibration procedure before
measurement onset. In this work a stereo approach is presented that yields the
position and orientation of the pupil in 3D space. This is achieved by
analyzing the pupil images of two calibrated cameras and by a subsequent
closed-form stereo reconstruction of the original pupil surface. Under the
assumption that the gaze-vector is parallel to the pupil normal vector, the
line of sight can be calculated without the need for the usual calibration that
requires the user to fixate targets with known spatial locations. Keywords: eye, gaze, pupil, stereo, tracking | |||
| Spatialchromatic foveation for gaze contingent displays | | BIBAK | Full-Text | 139-142 | |
| Sheng Liu; Hong Hua | |||
| Spatially variant resolution method has been widely explored for Gaze
Contingent Displays (GCDs). Recently several studies suggested that spatial
chromatic foveation can further improve the sampling efficiency and save
computational resources and communication bandwidths in GCDs. In this paper, we
explore the spatial variance of the contrast sensitivity function (CSF) of the
human visual system (HVS) to examine the potential of spatialchromatic
foveation in GCDs. The proposed algorithm reveals that, not only the spatial
resolution, but also the chrominance complexity can be monotonically degraded
from the center of the field of view (FOV) to the periphery of a GCD. A
perceptually-based spatialchromatic foveation metric is derived. Applying the
proposed hue-resolution foveation metric, we demonstrate that over 65% of
bandwidth can be saved. Keywords: color bytes, contrast sensitivity, gaze contingent display, hue | |||
| Using semantic content as cues for better scanpath prediction | | BIBAK | Full-Text | 143-146 | |
| Moran Cerf; E. Paxon Frady; Christof Koch | |||
| Under natural viewing conditions, human observers use shifts in gaze to
allocate processing resources to subsets of the visual input. There are many
computational models that try to predict these shifts in eye movement and
attention. Although the important role of high level stimulus properties (e.g.,
semantic information) stands undisputed, most models are based solely on
low-level image properties. We here demonstrate that a combined model of
high-level object detection and low-level saliency significantly outperforms a
low-level saliency model in predicting locations humans fixate on. The data is
based on eye-movement recordings of humans observing photographs of natural
scenes, which contained one of the following high-level stimuli: faces, text,
scrambled text or cell phones. We show that observers -- even when not
instructed to look for anything particular, fixate on a face with a probability
of over 80% within their first two fixations, on text and scrambled text with a
probability of over 65.1% and 57.9% respectively, and on cell phones with
probability of 8.3%. This suggests that content with meaningful semantic
information is significantly more likely to be seen earlier. Adding regions of
interest (ROI), which depict the locations of the high-level meaningful
features, significantly improves the prediction of a saliency model for stimuli
with high semantic importance, while it has little effect for an object with no
semantic meaning. Keywords: eye tracking, natural scenes, psychophysics | |||
| Eye2i: coordinated multiple views for gaze data | | BIBAK | Full-Text | 147 | |
| Harri Rantala | |||
| Different visualizations, such as gaze plots and heat maps, are prevalent
tools for analyzing gaze data. For complex and multi-variate data, the use of
coordinated multiple views is an efficient approach to visualizing information.
This paper presents a tool combining gaze data visualizations with coordinated
multiple-view methods for exploring gaze data. Keywords: coordinated multiple views, gaze data visualization, visual interaction | |||
| GInX: gaze based interface extensions | | BIBAK | Full-Text | 149-152 | |
| Thiago S. Barcelos; Carlos H. Morimoto | |||
| This paper introduces the Gaze based Interface Extensions (GInX)
architecture designed for the development of eye-gaze enhanced attentive
interfaces. The architecture is composed of 3 modules, the domain, user, and
attentive modules. In the absence of information about the user and the domain,
the attentive module controls the cursor using gaze and target position
information alone. The cursor control can be refined in an attentive way
[Vertegaal 2002] as more information about the application and the user are
added. The system currently offers 3 different operation modes: Latency, MAGIC,
and GInX default mode. In the Latency mode, the cursor position is controlled
by gaze and selection is done using dwell time. MAGIC Pointing [Zhai et al.
1999] was suggested to combine the speed of eye tracking with the accuracy of
manual pointing devices. GInX extends the concept of Magic Pointing by
introducing information about the user and application context in order to
eliminate the time required for cursor reacquisition and position adjustment
inherent in the original MAGIC Pointing interface. A prototype of GInX was
implemented and used to compared the performance of all these 3 modes with a
mouse. Our experiments show that GInX outperforms MAGIC Pointing, although the
mouse has the best performance overall. Keywords: gaze aware interfaces | |||
| An online noise filter for eye-tracker data recorded in a virtual environment | | BIBAK | Full-Text | 153-156 | |
| Sylvain Chartier; Patrice Renaud | |||
| A Recursive Online Weight Average filter (ROWA) is proposed to remove and
replace noisy data obtained from eye tracker. Since the filter can be
implemented online, it can detect and replace noisy data using solely past
records. Simulations results indicate that the filter achieved the same
performance compared to other standard offline filters while being simpler. Keywords: eye-blinks, eye-tracker, noise removal, online filtering | |||
| Cross-race recognition deficit and visual attention: do they all look (at faces) alike? | | BIBAK | Full-Text | 157-164 | |
| Sheree Josephson; Michael E. Holmes | |||
| An eye-tracking study was conducted to examine cross-race recognition
deficit (CRRD) or own-race bias in cross-racial eyewitness identification. It
is known in the legal community that cross-racial eyewitnesses are often wrong,
resulting in a number of erroneous convictions in the United States.
Forty participants in a racially diverse area of the U.S. watched a video of a property crime being committed and then returned about 24 hours later to pick the suspect out of a photo array while their eyes were tracked. A majority of participants misidentified the suspect or believed he was not in the lineup. Correct identifications were higher than expected when the eyewitness and suspect were of the same race. Conversely, misidentifications were higher than expected in the cross-race condition. Three clusters emerged from comparison of the eye-path sequences. A "quick and confident" cluster contained largely white eyewitnesses and white suspects. A "mixed results" cluster was largely cross-race cases. A "cautious confirmation" cluster consisted of more black eyewitnesses and black suspects. ANOVAs to analyze distribution of attention revealed a main effect only for eyewitness race. An interaction effect of eyewitness race and suspect race -- indicating a connection between visual attention and CRRD -- was not found. Keywords: cross-race recognition deficit, eye tracking, eyewitness, own-race bias,
visual attention | |||
| The visual span of chess players | | BIBAK | Full-Text | 165-171 | |
| P. J. Blignaut; T. R. Beelders; C-Y. So | |||
| As part of an effort to provide a framework for the advancement and
development of chess skills in young children and beginners an experiment was
undertaken to determine how the visual scanning of a chess board differs
between weaker and better players. The ELO rating system was used as an
independent variable in a series of chess problems that were presented to chess
players on a Tobii eye-tracker system.
It was found that stronger players perceive more squares with a single fixation and that they spend less time to inspect each square than weaker players. Also, the number of squares that are revisited is, at least for easier problems, significantly lower for players of higher strength. It appears that gaze patterns differ for more challenging problems. Keywords: chess, eye-tracking, visual span | |||
| Deixis and gaze in collaborative work at a distance (over a shared map): a computational model to detect misunderstandings | | BIBAK | Full-Text | 173-180 | |
| Mauro Cherubini; Marc-Antoine Nüssli; Pierre Dillenbourg | |||
| This paper presents an algorithm that detects misunderstandings in
collaborative work at a distance. It analyses the movements of collaborators'
eyes on the shared workspace, their utterances containing references about this
workspace, and the availability of 'remote' deictic gestures. This method is
based on two findings: 1. participants look at the points they are talking
about in their message; 2. their gazes are more dense around these points
compared to other random looks in the same timeframe. The algorithm associates
the distance between the gazes of the emitter and gazes of the receiver of a
message with the probability that the recipient did not understand the message. Keywords: computer-supported collaborative work, focus of attention, remote
collaborative tasks, remote deixis, spatial cognition | |||
| 3D point-of-regard, position and head orientation from a portable monocular video-based eye tracker | | BIBAK | Full-Text | 181-188 | |
| Susan M. Munn; Jeff B. Pelz | |||
| To study an observer's eye movements during realistic tasks, the observer
should be free to move naturally throughout our three-dimensional world.
Therefore, a technique to determine an observer's point-of-regard (POR) as well
as his/her motion throughout a scene in three dimensions with minor user input
is proposed. This requires robust feature tracking and calibration of the scene
camera in order to determine the 3D location and orientation of the scene
camera in the world. With this information, calibrated 2D PORs can be
triangulated to 3D positions in the world; the scale of the world coordinate
system can be obtained via input of the distance between two known points in
the scene. Information about scene camera movement and tracked features can
also be used to obtain observer position and head orientation for all video
frames. The final observer motion -- including the observer's positions and
head orientations -- and PORs are expressed in 3D world coordinates. The result
is knowledge of not only eye movements but head movements as well allowing for
the evaluation of how an observer combines head and eye movements to perform a
visual task. Additionally, knowledge of 3D information opens the door for many
more options for visualization of eye-tracking results. Keywords: ego-motion, eye tracking, eye-head coordination, head orientation,
point-of-regard, three-dimensional | |||
| A robust 3D eye gaze tracking system using noise reduction | | BIBAK | Full-Text | 189-196 | |
| Jixu Chen; Yan Tong; Wayne Gray; Qiang Ji | |||
| This paper describes a novel real-time 3D gaze estimation system. The system
consists of two cameras and two IR light sources. There are three novelties in
this method. First, in our system, two IR lights are mounted near the centers
of the stereo cameras, respectively. Based on this specific configuration, the
3D position of the corneal center can be simply derived by the 3D
reconstruction technique. Then, after extracting the 3D position of the
"virtual pupil" correctly, the optical axis of the eye can be obtained directly
by connecting the "virtual pupil" with the corneal center. Second, we
systematically analyze the noise in our 3D gaze estimation algorithm and
propose an effective constraint to reduce this noise. Third, to estimate the
user-dependent parameters (i.e. the constraint parameters and the eye
parameters), a simple calibration method is proposed by gazing at four
positions on the screen. Experimental results show that our system can
accurately estimate and track eye gaze under natural head movement. Keywords: gaze estimation, noise reduction, stereo cameras | |||
| A new "wireless" search-coil system | | BIBAK | Full-Text | 197-204 | |
| Dale Roberts; Mark Shelhamer; Aaron Wong | |||
| The scleral search-coil system is the accepted standard for precise and
accurate recording of eye movements in the lab and clinic. One of the drawbacks
of this system is the connecting wire that leads from the eye coil to the
associated electronics; this wire causes irritation to the subject and has a
tendency to break during experiments. We have developed a modified version of
this technique, which uses a resonant scleral coil and no connecting wire. A
transmitter sends a stream of pulses to the eye coil, and a receiver then
detects the resonant oscillations re-radiated from the eye coil. The relative
intensity of the signal as received by sets of orthogonal receiver coils
determines the orientation of the eye coil. The new approach retains the
advantages of accuracy, precision, and high sample rate, while making the
system portable and more comfortable. Keywords: contact lens, eye movements, eye tracking, magnetic fields, scleral search
coil, wireless coil | |||
| Noise tolerant selection by gaze-controlled pan and zoom in 3D | | BIBAK | Full-Text | 205-212 | |
| Dan Witzner Hansen; Henrik H. T. Skovsgaard; John Paulin Hansen; Emilie Møllenbach | |||
| This paper presents StarGazer -- a new 3D interface for gaze-based
interaction and target selection using continuous pan and zoom. Through
StarGazer we address the issues of interacting with graph structured data and
applications (i.e. gaze typing systems) using low resolution eye trackers or
small-size displays. We show that it is possible to make robust selection even
with a large number of selectable items on the screen and noisy gaze trackers.
A test with 48 subjects demonstrated that users who have never tried gaze
interaction before could rapidly adapt to the navigation principles of
StarGazer. We tested three different display sizes (down to PDA-sized displays)
and found that large screens are faster to navigate than small displays and
that the error rate is higher for the smallest display. Half of the subjects
were exposed to severe noise deliberately added on the cursor positions. We
found that this had a negative impact on efficiency. However, the user remained
in control and the noise did not seem to effect the error rate. Additionally,
three subjects tested the effects of temporally adding noise to simulate
latency in the gaze tracker. Even with a significant latency (about 200 ms) the
subjects were able to type at acceptable rates. In a second test, seven
subjects were allowed to adjust the zooming speed themselves. They achieved
typing rates of more than eight words per minute without using language
modeling. We conclude that the StarGazer application is an intuitive 3D
interface for gaze navigation, allowing more selectable objects to be displayed
on the screen than the accuracy of the gaze trackers would otherwise permit. Keywords: 3D interfaces, alternative communication, assistive technology, computer
input devices, eye tracking, eye typing, gaze interaction, mobile displays,
zooming | |||
| Looking my way through the menu: the impact of menu design and multimodal input on gaze-based menu selection | | BIBAK | Full-Text | 213-220 | |
| Yvonne Kammerer; Katharina Scheiter; Wolfgang Beinhauer | |||
| In this paper a study is reported, which investigates the effectiveness of
two approaches to improving gaze-based interaction for realistic and complex
menu selection tasks. The first approach focuses on identifying menu designs
for hierarchical menus that are particularly suitable for gaze-based
interaction, whereas the second approach is based on the idea of combining
gaze-based interaction with speech as a second input modality. In an experiment
with 40 participants the impact of menu design, input device, and navigation
complexity on accuracy and completion time in a menu selection task as well as
on user satisfaction were investigated. The results concerning both objective
task performance and subjective ratings confirmed our expectations in that a
semi-circle menu was better suited for gaze-based menu selection than either a
linear or a full-circle menu. Contrary to our expectations, an input device
solely based on eye gazes turned out to be superior to the combined gaze- and
speech-based device. Moreover, the drawbacks of a less suitable menu design
(i.e., of a linear menu or a full-circle menu) as well as of the multimodal
input device particularly obstructed performance in the case of more complex
navigational tasks. Keywords: circular menus, gaze-based interaction, menu selection, multimodal input,
usability | |||
| Snap clutch, a moded approach to solving the Midas touch problem | | BIBAK | Full-Text | 221-228 | |
| Howell Istance; Richard Bates; Aulikki Hyrskykari; Stephen Vickers | |||
| 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. Keywords: disabled users, eye tracking, feedback, gaze control, gaze gestures | |||
| Eye movement prediction by Kalman filter with integrated linear horizontal oculomotor plant mechanical model | | BIBAK | Full-Text | 229-236 | |
| Oleg V. Komogortsev; Javed I. Khan | |||
| The goal of this paper is to predict future horizontal eye movement
trajectories within a specified time interval. To achieve this goal a linear
horizontal oculomotor plant mechanical model is developed. The model consists
of the eye globe and two extraocular muscles: lateral and medial recti. The
model accounts for such anatomical properties of the eye as muscle location,
elasticity, viscosity, eye-globe rotational inertia, muscle active state
tension, length tension and force velocity relationships. The mathematical
equations describing the oculomotor plant mechanical model are transformed into
a Kalman filter form. Such transformation provides continuous eye movement
prediction with a high degree of accuracy. The model was tested with 21
subjects and three multimedia files. Practical application of this model lies
with direct eye gaze input and interactive displays systems as a method to
compensate for detection, transmission and processing delays. Keywords: Kalman filter, eye movement prediction, human computer interaction,
oculomotor plant | |||
| Analysis of subject-dependent point-of-gaze estimation bias in the cross-ratios method | | BIBAK | Full-Text | 237-244 | |
| Elias D. Guestrin; Moshe Eizenman; Jeffrey J. Kang; Erez Eizenman | |||
| The cross-ratios method for point-of-gaze estimation uses the invariance
property of cross-ratios in projective transformations. The inherent causes of
the subject-dependent point-of-gaze estimation bias exhibited by this method
have not been well characterized in the literature. Using a model of the eye
and the components of a system (camera, light sources) that estimates
point-of-gaze, a theoretical framework for the cross-ratios method is
developed. The analysis of the cross-ratios method within this framework shows
that the subject-dependent estimation bias is caused mainly by (i) the angular
deviation of the visual axis from the optic axis and (ii) the fact that the
virtual image of the pupil center is not coplanar with the virtual images of
the light sources that illuminate the eye (corneal reflections). The
theoretical framework provides a closed-form analytical expression that
predicts the estimation bias as a function of subject-specific eye parameters. Keywords: cross-ratios, eye model, eye parameters, point-of-gaze, remote gaze
estimation | |||
| Remote gaze estimation with a single camera based on facial-feature tracking without special calibration actions | | BIBAK | Full-Text | 245-250 | |
| Hirotake Yamazoe; Akira Utsumi; Tomoko Yonezawa; Shinji Abe | |||
| We propose a real-time gaze estimation method based on facial-feature
tracking using a single video camera that does not require any special user
action for calibration. Many gaze estimation methods have been already
proposed; however, most conventional gaze tracking algorithms can only be
applied to experimental environments due to their complex calibration
procedures and lacking of usability. In this paper, we propose a gaze
estimation method that can apply to daily-life situations. Gaze directions are
determined as 3D vectors connecting both the eyeball and the iris centers.
Since the eyeball center and radius cannot be directly observed from images,
the geometrical relationship between the eyeball centers and the facial
features and eyeball radius (face/eye model) are calculated in advance. Then,
the 2D positions of the eyeball centers can be determined by tracking the
facial features. While conventional methods require instructing users to
perform such special actions as looking at several reference points in the
calibration process, the proposed method does not require such special
calibration action of users and can be realized by combining 3D eye-model-based
gaze estimation and circle-based algorithms for eye-model calibration.
Experimental results show that the gaze estimation accuracy of the proposed
method is 5° horizontally and 7° vertically. With our proposed method,
various application such as gaze-communication robots, gaze-based interactive
signboards, etc. that require gaze information in daily-life situations are
possible. Keywords: daily-life situations, non-intrusive, remote gaze tracking | |||
| A software framework for simulating eye trackers | | BIBAK | Full-Text | 251-258 | |
| Martin Böhme; Michael Dorr; Mathis Graw; Thomas Martinetz; Erhardt Barth | |||
| We describe an open-source software framework that simulates the
measurements made using one or several cameras in a video-oculographic eye
tracker. The framework can be used to compare objectively the performance of
different eye tracking setups (number and placement of cameras and light
sources) and gaze estimation algorithms. We demonstrate the utility of the
framework by using it to compare two remote eye tracking methods, one using a
single camera, the other using two cameras. Keywords: eye tracking, gaze estimation, optical simulation | |||
| Taxonomic study of polynomial regressions applied to the calibration of video-oculographic systems | | BIBAK | Full-Text | 259-266 | |
| Juan J. Cerrolaza; Arantxa Villanueva; Rafael Cabeza | |||
| Of gaze tracking techniques, video-oculography (VOG) is one of the most
attractive because of its versatility and simplicity. VOG systems based on
general purpose mapping methods use simple polynomial expressions to estimate a
user's point of regard. Although the behaviour of such systems is generally
acceptable, a detailed study of the calibration process is needed to facilitate
progress in improving accuracy and tolerance to user head movement. To date,
there has been no thorough comparative study of how mapping equations affect
final system response. After developing a taxonomic classification of
calibration functions, we examine over 400,000 models and evaluate the validity
of several conventional assumptions. The rigorous experimental procedure
employed enabled us to optimize the calibration process for a real VOG gaze
tracking system and, thereby, halve the calibration time without detrimental
effect on accuracy or tolerance to head movement. Keywords: calibration, gaze tracking, multiple linear regression, polynomial equation,
taxonomic classification, video-oculographic | |||
| Remote point-of-gaze estimation requiring a single-point calibration for applications with infants | | BIBAK | Full-Text | 267-274 | |
| Elias Daniel Guestrin; Moshe Eizenman | |||
| This paper describes a method for remote, non-contact point-of-gaze
estimation that tolerates free head movements and requires a simple calibration
procedure in which the subject has to fixate only on a single point. This
method uses the centers of the pupil and at least two corneal reflections that
are estimated from eye images captured by at least two cameras. Experimental
results obtained with three adult subjects exhibited RMS point-of-gaze
estimation errors ranging from 7 to 12 mm (equivalent to about 0.6-1° of
visual angle) for head movements in a volume of about 1 dm3. Preliminary
results with two infants demonstrated the ability of a system that requires a
single-point calibration procedure to estimate infants' point-of-gaze. The
ability to record infants' visual scanning behavior can be used for the study
of visual development, the determination of attention allocation and the
assessment of visual function in preverbal infants. Keywords: infants' gaze, minimal subject cooperation, point-of-gaze, remote gaze
estimation, single-point calibration | |||