| Vision in natural and virtual environments | | BIBAK | Full-Text | 7-13 | |
| Mary M. Hayhoe; Dana H. Ballard; Jochen Triesch; Hiroyuki Shinoda; Pilar Aivar; Brian Sullivan | |||
| Our knowledge of the way that the visual system operates in everyday
behavior has, until recently, been very limited. This information is critical
not only for understanding visual function, but also for understanding the
consequences of various kinds of visual impairment, and for the development of
interfaces between human and artificial systems. The development of eye
trackers that can be mounted on the head now allows monitoring of gaze without
restricting the observer's movements. Observations of natural behavior have
demonstrated the highly task-specific and directed nature of fixation patterns,
and reveal considerable regularity between observers. Eye, head, and hand
coordination also reveals much greater flexibility and task-specificity than
previously supposed. Experimental examination of the issues raised by
observations of natural behavior requires the development of complex virtual
environments that can be manipulated by the experimenter at critical points
during task performance. Experiments where we monitored gaze in a simulated
driving environment demonstrate that visibility of task relevant information
depends critically on active search initiated by the observer according to an
internally generated schedule, and this schedule depends on learnt regularities
in the environment. In another virtual environment where observers copied toy
models we showed that regularities in the spatial structure are used by
observers to control eye movement targeting. Other experiments in a virtual
environment with haptic feedback show that even simple visual properties like
size are not continuously available or processed automatically by the visual
system, but are dynamically acquired and discarded according to the momentary
task demands. Keywords: attention, saccadic targeting, virtual environments | |||
| Twenty years of eye typing: systems and design issues | | BIBAK | Full-Text | 15-22 | |
| Päivi Majaranta; Kari-Jouko Räihä | |||
| Eye typing provides a means of communication for severely handicapped
people, even those who are only capable of moving their eyes. This paper
considers the features, functionality and methods used in the eye typing
systems developed in the last twenty years. Primary concerned with text
production, the paper also addresses other communication related issues, among
them customization and voice output. Keywords: Eye typing, alternative communication, eye tracking | |||
| Designing attentive interfaces | | BIBAK | Full-Text | 23-30 | |
| Roel Vertegaal | |||
| In this paper, we propose a tentative framework for the classification of
Attentive Interfaces, a new category of user interfaces. An Attentive Interface
is a user interface that dynamically prioritizes the information it presents to
its users, such that information processing resources of both user and system
are optimally distributed across a set of tasks. The interface does this on the
basis of knowledge -- consisting of a combination of measures and models -- of
the past, present and future state of the user's attention, given the
availability of system resources. We will show how the Attentive Interface
provides a natural extension to the windowing paradigm found in Graphical User
Interfaces. Our taxonomy of Attentive Interfaces allows us to identify classes
of user interfaces that would benefit most from the ability to sense, model and
optimize the user's attentive state. In particular, we show how systems that
influence user workflow in concurrent task situations, such as those involved
with management of multiparty communication, may benefit from such facilities. Keywords: Attention, Attentive Interfaces, Eye Tracking, Nonverbal Computing, User
Interfaces | |||
| Fixation maps: quantifying eye-movement traces | | BIBAK | Full-Text | 31-36 | |
| David S. Wooding | |||
| The analysis of eye-movement traces (i.e. the patterns of fixations in a
search) is a powerful but often neglected area of eye-movement research. This
is largely because it requires a more complex analysis than parameters such as
mean fixation duration and as a result, previous attempts have focused on
qualitative appraisal of the form of an eye-movement trace. In this paper, we
introduce the concept of the "fixation map". We discuss its application to the
quantification of similarity of traces, and the degree of "coverage" by
fixations of a visual stimulus. The use of fixation maps in the understanding
and communication of large numbers of eye-movement traces is also examined. Keywords: Eye-movements, analysis, fixation map, similarity, traces | |||
| The act of task difficulty and eye-movement frequency for the 'Oculo-motor indices' | | BIBAK | Full-Text | 37-42 | |
| Minoru Nakayama; Koji Takahashi; Yasutaka Shimizu | |||
| The oculo-motor reflects the viewer's ability to process visual information.
This paper examines whether the oculo-motor was affected by two factors:
firstly task difficulty and secondly eye-movement frequency. In this paper,
oculo-motor indices were defined as measurements of pupil size, blink and
eye-movement. For the purpose of this study, two experiments were designed
based on previous subsequential ocular tasks where subjects were required to
solve a series of mathematical problems and to orally report their
calculations.
The results of this experiment found that pupil size and blink rate increased in response to task difficulty in the oral calculation group. In contrast, however, both the saccade occurrence rate and saccade length were found to decrease with the increased difficulty of the task. The results suggests that oculo-motor indices respond to task difficulty. Secondly, eye-movement frequencies were elicited by the switching frequency of a visual target. Pupil size and the saccade time were found to increase with the frequency however, blink and gazing time were found to decrease in response to the frequency. There was a negative correlation between blinking and gazing time. Additionally, the correlation between blinking and saccade time appeared in the higher frequencies. These results indicate the oculo-motor indices are affected by both task difficulty and eye-movement frequency. Furthermore, eye-movement frequency appears to play a different role than that of task difficulty. Keywords: Blink, Eye-movement, Gaze, Pupil Size, Saccade | |||
| Visual attention to repeated internet images: testing the scanpath theory on the world wide web | | BIBAK | Full-Text | 43-49 | |
| Sheree Josephson; Michael E. Holmes | |||
| The somewhat controversial and often-discussed theory of visual perception,
that of scanpaths, was tested using Web pages as visual stimuli. In 1971, Noton
and Stark defined "scanpaths" as repetitive sequences of fixations and saccades
that occur upon re-exposure to a visual stimulus, facilitating recognition of
that stimulus. Since Internet users are repeatedly exposed to certain visual
displays of information, the Web is an ideal stimulus to test this theory.
Eye-movement measures were recorded while subjects repeatedly viewed three
different kinds of Internet pages -- a portal page, an advertising page and a
news story page -- over the course of a week. Scanpaths were compared by using
the string-edit methodology that measures resemblance between sequences.
Findings show that on the World Wide Web, with somewhat complex visual digital
images, some viewers' eye movements may follow a habitually preferred path -- a
scanpath -- across the visual display. In addition, strong similarity among
eye-path sequences of different viewers may indicate that other forces such as
features of the Web site or memory are important. Keywords: Eye movement, Internet imagery, World Wide Web, eye tracking, optimal
matching analysis, scanpath, sequence comparison, string editing | |||
| Eye tracking in web search tasks: design implications | | BIBAK | Full-Text | 51-58 | |
| Joseph H. Goldberg; Mark J. Stimson; Marion Lewenstein; Neil Scott; Anna M. Wichansky | |||
| An eye tracking study was conducted to evaluate specific design features for
a prototype web portal application. This software serves independent web
content through separate, rectangular, user-modifiable portlets on a web page.
Each of seven participants navigated across multiple web pages while conducting
six specific tasks, such as removing a link from a portlet. Specific
experimental questions included (1) whether eye tracking-derived parameters
were related to page sequence or user actions preceding page visits, (2)
whether users were biased to traveling vertically or horizontally while viewing
a web page, and (3) whether specific sub-features of portlets were visited in
any particular order. Participants required 2-15 screens, and from 7-360+
seconds to complete each task. Based on analysis of screen sequences, there was
little evidence that search became more directed as screen sequence increased.
Navigation among portlets, when at least two columns exist, was biased towards
horizontal search (across columns) as opposed to vertical search (within
column). Within a portlet, the header bar was not reliably visited prior to the
portlet's body, evidence that header bars are not reliably used for navigation
cues. Initial design recommendations emphasized the need to place critical
portlets on the left and top of the web portal area, and that related portlets
do not need to appear in the same column. Further experimental replications are
recommended to generalize these results to other applications. Keywords: Eye Tracking, Software, Usability Evaluation, World Wide Web | |||
| What do the eyes behold for human-computer interaction? | | BIBA | Full-Text | 59-60 | |
| Roel Vertegaal | |||
| In recent years, there has been a resurgence of interest in the use of eye tracking systems for interactive purposes. However, it is easy to be fooled by the interactive power of eye tracking. When first encountering eye based interaction, most people are genuinely impressed with the almost magical window into the mind of the user that it seems to provide. There are two reasons why this belief may lead to subsequent disappointment. Firstly, although current eye tracking equipment is far superior to that used in the seventies and early eighties, it is by no means perfect. For example, there is still the tradeoff between the use of an obtrusive head-based system or a desk-based system with limited head movement. Such technical problems continue to limit the usefulness of eye tracking as a generic form of input. Secondly, there are real methodological problems regarding the interpretation of eye input for use in graphical user interfaces. One example, the "Midas Touch" problem, is observed in systems that use eye movements to directly control a mouse cursor. When does the system decide that a user is interested in a visual object? Systems that implement dwell time for this purpose run the risk of disallowing visual scanning behavior, requiring users to control their eye movements for the purposes of output, rather than input. However, difficulties in the interpretation of visual interest remain even when systems use another input modality for signaling intent. Another classic methodological problem is exemplified by the application of eye movement recording in usability studies. Although eye fixations provide some of the best measures of visual interest, they do not provide a measure of cognitive interest. It is one thing to determine whether a user has observed certain visual information, but quite another to determine whether this information has in fact been processed or understood. Some of our technological problems can and will be solved. However, we believe that our methodological issues point to a more fundamental problem: What is the nature of the input information conveyed by eye movements and to what interactive functions can this information provide added value? | |||
| On-road driver eye movement tracking using head-mounted devices | | BIBAK | Full-Text | 61-68 | |
| M. Sodhi; B. Reimer; J. L. Cohen; E. Vastenburg; R. Kaars; S. Kirschenbaum | |||
| It is now evident from anecdotal evidence and preliminary research that
distractions can hinder the task of operating a vehicle, and consequently
reduce driver safety. However with increasing wireless connectivity and the
portability of office devices, the vehicle of the future is visualized as an
extension of the static work place -- i.e. an office-on-the-move, with a phone,
a fax machine and a computer all within the reach of the vehicle operator. For
this research a Head mounted Eye-tracking Device (HED), is used for tracking
the eye movements of a driver navigating a test route in an automobile while
completing various driving tasks. Issues arising from data collection of eye
movements during the completion of various driving tasks as well as the
analysis of this data are discussed. Methods for collecting video and scan-path
data, as well as difficulties and limitations are also reported. Keywords: Camera calibration, Ergonomics, Perceptual reasoning, Tracking | |||
| A software-based eye tracking system for the study of air-traffic displays | | BIBAK | Full-Text | 69-76 | |
| Jeffrey B. Mulligan | |||
| This paper describes a software-based system for offline tracking of eye and
head movements using stored video images, designed for use in the study of
air-traffic displays. These displays are typically dense with information; to
address the research questions, we wish to be able to localize gaze within a
single word within a line of text (a few minutes of arc), while at the same
time allowing some freedom of movement to the subject. Accurate gaze tracking
in the presence of head movements requires high precision head tracking, and
this was accomplished by registration of images from a forward-looking scene
camera with a narrow field of view. Keywords: Head and eye tracking, air traffic displays, image registration, scan-path
analysis | |||
| Eye gaze correction for videoconferencing | | BIBAK | Full-Text | 77-81 | |
| Jason Jerald; Mike Daily | |||
| This paper describes a 2D videoconferencing system with eye gaze correction.
Tracking the eyes and warping the eyes appropriately each frame appears to
create natural eye contact between users. The geometry of the eyes as well as
the displacement of the camera with the remote user's image determines the
warp. We implement this system within software, not requiring any specialized
hardware. Keywords: Videoconferencing, eye contact, eye tracking, gaze correction, mutual gaze,
nonverbal social interaction, telepresence | |||
| Real-time simulation of arbitrary visual fields | | BIBAK | Full-Text | 83-87 | |
| Wilson S. Geisler; Jeffrey S. Perry | |||
| This report describes an algorithm and software for creating and displaying,
in real time, arbitrary variable resolution displays, contingent on the
direction of gaze. The software produces precise, artifact-free video at high
frame rates in either 8-bit gray scale or 24-bit color. The software is
demonstrated by simulating the visual fields of normal individuals and
low-vision patients. Keywords: eye disease, eye movements, foveated imaging, gaze contingent display, low
vision, variable resolution image, visual fields | |||
| Reduced saliency of peripheral targets in gaze-contingent multi-resolutional displays: blended versus sharp boundary windows | | BIBAK | Full-Text | 89-93 | |
| Eyal M. Reingold; Lester C. Loschky | |||
| Gaze-contingent multi-resolutional displays (GCMRDs) have been proposed to
solve the processing and bandwidth bottleneck in many single-user displays, by
dynamically placing high-resolution in a window at the center of gaze, with
lower resolution everywhere else. GCMRDs are also useful for investigating the
perceptual processes involved in natural scene viewing. Several such studies
suggest that potential saccade targets in degraded regions are less salient
than those in the high-resolution window. Consistent with this, Reingold,
Loschky, Stampe and Shen [2001b] found longer initial saccadic latencies to a
salient peripheral target in conditions with a high-resolution window and
degraded surround than in an all low-pass filtered no-window condition.
Nevertheless, these results may have been due to parafoveal load caused by
saliency of the boundary between the high- and low-resolution areas. The
current study extends Reingold, et al. [2001b] by comparing both sharp- and
blended-resolution boundary conditions with an all low-resolution no-window
condition. The results replicate the previous findings [Reingold et al. 2001b]
but indicate that the effect is unaltered by the type of window boundary (sharp
or blended). This rules out the parafoveal load hypothesis, while further
supporting the hypothesis that potential saccade targets in the degraded region
are less salient than those in the high-resolution region. Keywords: area of interest, bi-resolution displays, dual-resolution displays, eye
movements, eyetracking, high-detail inset, multi-resolutional displays,
peripheral degradation, peripheral vision, saliency, variable resolution
displays, visual perception, visual search | |||
| Saccade contingent updating in virtual reality | | BIBAK | Full-Text | 95-102 | |
| Jochen Triesch; Brian T. Sullivan; Mary M. Hayhoe; Dana H. Ballard | |||
| We are interested in saccade contingent scene updates where the visual
information presented in a display is altered while a saccadic eye movement of
an unconstrained, freely moving observer is in progress. Since saccades
typically last only several tens of milliseconds depending on their size, this
poses difficult constraints on the latency of detection. We have integrated two
complementary eye trackers in a virtual reality helmet to simultaneously 1)
detect saccade onsets with very low latency and 2) track the gaze with high
precision albeit higher latency. In a series of experiments we demonstrate the
system s capability of detecting saccade onsets with sufficiently low latency
to make scene changes while a saccade is still progressing. While the method
was developed to facilitate studies of human visual perception and attention,
it may nd interesting applications in human-computer interaction and computer
graphics. Keywords: change blindness, eye tracking, limbus tracking, saccade contingent
updating, saccades, virtual reality | |||
| 3D eye movement analysis for VR visual inspection training | | BIBA | Full-Text | 103-110 | |
| Andrew T. Duchowski; Eric Medlin; Nathan Cournia; Anand Gramopadhye; Brian Melloy; Santosh Nair | |||
| This paper presents an improved 3D eye movement analysis algorithm for binocular eye tracking within Virtual Reality for visual inspection training. The user's gaze direction, head position and orientation are tracked to allow recording of the user's fixations within the environment. The paper summarizes methods for (1) integrating the eye tracker into a Virtual Reality framework, (2) calculating the user's 3D gaze vector, and (3) calibrating the software to estimate the user's inter-pupillary distance post-facto. New techniques are presented for eye movement analysis in 3D for improved signal noise suppression. The paper describes (1) the use of Finite Impulse Response (FIR) filters for eye movement analysis, (2) the utility of adaptive thresholding and fixation grouping, and (3) a heuristic method to recover lost eye movement data due to miscalibration. While the linear signal analysis approach is itself not new, its application to eye movement analysis in three dimensions advances traditional 2D approaches since it takes into account the 6 degrees of freedom of head movements and is resolution independent. Results indicate improved noise suppression over our previous signal analysis approach. | |||
| What attracts the eye to the location of missed and reported breast cancers? | | BIBA | Full-Text | 111-117 | |
| Claudia Mello-Thoms; Calvin F. Nodine; Harold L. Kundel | |||
| The primary detector of breast cancer is the human eye, as it examines mammograms searching for signs of the disease. Nonetheless, it has been shown that 10-30% of all cancers in the breast are not reported by the radiologist, even though most of these are visible retrospectively. Studies of eye position have shown that the eye tends to dwell in the locations of both reported and not reported cancers, indicating that the problem is not faulty visual search, but rather, that is primarily related to perceptual and decision making mechanisms. In this paper we model the areas that attracted the radiologists' visual attention when reading mammograms and that yielded a decision by the radiologist, being this decision overt or covert. We contrast the characteristics of areas that contain cancers that were reported from the ones that contain cancers that, albeit attracting attention, did not reach an internal conspicuity threshold to be reported. | |||
| Visual search: structure from noise | | BIBAK | Full-Text | 119-123 | |
| Umesh Rajashekar; Lawrence K. Cormack; Alan C. Bovik | |||
| In this paper, we present two techniques to reveal image features that
attract the eye during visual search: the discrimination image paradigm and
principal component analysis. In preliminary experiments, we employed these
techniques to identify image features used to identify simple targets embedded
in 1/ƒ noise. Two main findings emerged. First, the loci of fixations were
not random but were driven by local image features, even in very noisy
displays. Second, subjects often searched for a component feature of a target
rather that the target itself, even if the target was a simple geometric form.
Moreover, the particular relevant component varied from individual to
individual. Also, principal component analysis of the noise patches at the
point of fixation reveals global image features used by the subject in the
search task. In addition to providing insight into the human visual system,
these techniques have relevance for machine vision as well. The efficacy of a
foveated machine vision system largely depends on its ability to actively
select 'visually interesting' regions in its environment. The techniques
presented in this paper provide valuable low-level criteria for executing
human-like scanpaths in such machine vision systems. Keywords: 1/ƒ noise, Discrimination Images, Eye movements, Principal Component
Analysis, Visual Search | |||
| FreeGaze: a gaze tracking system for everyday gaze interaction | | BIBAK | Full-Text | 125-132 | |
| Takehiko Ohno; Naoki Mukawa; Atsushi Yoshikawa | |||
| In this paper we introduce a novel gaze tracking system called FreeGaze,
which is designed for the use of everyday gaze interaction. Among various
possible applications of gaze tracking system, Human-Computer Interaction (HCI)
is one of the most promising fields. However, existing systems require
complicated and burden-some calibration and are not robust to the measurement
variations. To solve these problems, we introduce a geometric eyeball model and
sophisticated image processing. Unlike existing systems, our system needs only
two points for each individual calibration. When the personalization finishes,
our system needs no more calibration before each measurement session.
Evaluation tests show that the system is accurate and applicable to everyday
use for the applications. Keywords: FreeGaze, Gaze tracing system, gaze interaction, the eyeball model | |||
| Differences in the infrared bright pupil response of human eyes | | BIBAK | Full-Text | 133-138 | |
| Karlene Nguyen; Cindy Wagner; David Koons; Myron Flickner | |||
| In this paper, we describe experiments conducted to explain observed
differences in the bright pupil response of human eyes. Many people observe the
bright pupil response as the red-eye effect when taking flash photography.
However, there is significant variation in the magnitude of the bright pupil
response across the population. Since many commercial gaze-tracking systems use
the infrared bright pupil response for eye detection, a clear understanding of
the magnitude and cause of the bright pupil variation gives critical insight
into the robustness of gaze tracking systems. This paper documents studies we
have conducted to measure the bright pupil differences using infrared light and
hypothesis factors that lead to these differences. Keywords: Gaze tracking, bright pupil response, eye tracking, red-eye effect,
retro-reflective pupil response | |||
| Real-time eye detection and tracking under various light conditions | | BIBAK | Full-Text | 139-144 | |
| Zhiwei Zhu; Kikuo Fujimura; Qiang Ji | |||
| Non-intrusive methods based on active remote IR illumination for eye
tracking are important for many applications of vision-based man-machine
interaction. One problem that has plagued those methods is their sensitivity to
lighting condition change. This tends to significantly limit their scope of
application. In this paper, we present a new real-time eye detection and
tracking methodology that works under variable and realistic lighting
conditions. Based on combining the bright-pupil effect resulted from IR light
and the conventional appearance-based object recognition technique, our method
can robustly track eyes when the pupils are not very bright due to significant
external illumination interferences. The appearance model is incorporated in
both eyes detection and tracking via the use of support vector machine and the
mean shift tracking. Additional improvement is achieved from modifying the
image acquisition apparatus including the illuminator and the camera. Keywords: Eye Tracking, Kalman Filter, Mean Shift, Support Vector Machine | |||