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ETRA Tables of Contents: 000204060810121416

Proceedings of the 2004 Symposium on Eye Tracking Research & Applications

Fullname:Proceedings of the 2004 Symposium Eye Tracking Research & Applications
Editors:Andrew T. Duchowski; Roel Vertegaal
Location:San Antonio, Texas, USA
Dates:2004-Mar-22 to 2004-Mar-24
Publisher:ACM
Standard No:ISBN: 1-58113-825-3; ACM DL: Table of Contents hcibib: ETRA04
Papers:28
Pages:154
Links:Conference Series Home Page
Preface BIBFull-Text 6
  Andrew Duchowski; Roel Vertegaal
Eye movements as reflections of perceptual and cognitive processes BIBAFull-Text 9-10
  Keith Rayner
Some historical issues regarding the use of eye movements to study cognitive processes will initially be discussed. The development of eye contingent display change experiments will be reviewed and examples will be presented regarding how the development of the technique provided answers to interesting questions. For the most part, examples will be taken from the psychology of reading, but other tasks will also be discussed. More recently, sophisticated models of eye movement control in the context of reading have been developed, and these models will be discussed. Some thoughts on future directions of eye movement research will also be presented.
Note: abstract only
Gaze-contingent display using texture mapping and OpenGL: system and applications BIBAKFull-Text 11-18
  Stavri G. Nikolov; Timothy D. Newman; Dave R. Bull; Nishan C. Canagarajah; Michael G. Jones; Iain D. Gilchrist
This paper describes a novel gaze-contingent display (GCD) using texture mapping and OpenGL. This new system has a number of key features: (a) it is platform independent, i.e. it runs on different computers and under different operating systems; (b) it is eyetracker independent, since it provides an interactive focus+context display that can be easily integrated with any eye-tracker that provides real-time 2-D gaze estimation; (c) it is flexible in that it provides for straightforward modification of the main GCD parameters, including size and shape of the window and its border; and (d) through the use of OpenGL extensions it can perform local real-time image analysis within the GCD window. The new GCD system implementation is described in detail and some performance figures are given. Several applications of this system are studied, including gaze-contingent multi-resolution displays, gaze-contingent multi-modality displays, and gaze-contingent image analysis.
Keywords: display, eye-tracking, gaze-contingent, image analysis, image compression, image fusion, openGL, texture mapping
A gaze contingent environment for fostering social attention in autistic children BIBAKFull-Text 19-26
  Rameshsharma Ramloll; Cheryl Trepagnier; Marc Sebrechts; Andreas Finkelmeyer
This paper documents the engineering of a gaze contingent therapeutic environment for the exploration and validation of a proposed rehabilitative technique addressing attention deficits in 24 to 54 months old autistic subjects. It discusses the current state of progress and lessons learnt so far while highlighting the outstanding engineering challenges of this project. We focus on calibration issues for this target group of users, explain the architecture of the system and present our general workflow for the construction of the gaze contingent environment. While this work is being undertaken for therapeutic purposes, it is likely to be relevant to the construction of gaze contingent displays for entertainment.
Keywords: attention, autism, design workflow, eye tracker calibration, gaze contingent environment
Robust clustering of eye movement recordings for quantification of visual interest BIBAKFull-Text 27-34
  Anthony Santella; Doug DeCarlo
Characterizing the location and extent of a viewer's interest, in terms of eye movement recordings, informs a range of investigations in image and scene viewing. We present an automatic data-driven method for accomplishing this, which clusters visual point-of-regard (POR) measurements into gazes and regions-of-interest using the mean shift procedure. Clusters produced using this method form a structured representation of viewer interest, and at the same time are replicable and not heavily influenced by noise or outliers. Thus, they are useful in answering fine-grained questions about where and how a viewer examined an image.
Keywords: clustering, eye movement analysis, mean shift, measures of visual interest
Visual deictic reference in a collaborative virtual environment BIBAFull-Text 35-40
  Andrew T. Duchowski; Nathan Cournia; Brian Cumming; Daniel McCallum; Anand Gramopadhye; Joel Greenstein; Sajay Sadasivan; Richard A. Tyrrell
This paper evaluates the use of Visual Deictic Reference (VDR) in Collaborative Virtual Environments (CVEs). A simple CVE capable of hosting two (or more) participants simultaneously immersed in the same virtual environment is used as the testbed. One participant's VDR, obtained by tracking the participant's gaze, is projected to co-participants' environments in real-time as a colored lightspot. We compare the VDR lightspot when it is eye-slaved to when it is head-slaved and show that an eye-slaved VDR helps disambiguate the deictic point of reference, especially during conditions when the user's line of sight is decoupled from their head direction.
Eye gaze patterns differentiate novice and experts in a virtual laparoscopic surgery training environment BIBAKFull-Text 41-48
  Benjamin Law; M. Stella Atkins; A. E. Kirkpatrick; Alan J. Lomax
Visual information is important in surgeons' manipulative performance especially in laparoscopic surgery where tactual feedback is less than in open surgery. The study of surgeons' eye movements is an innovative way of assessing skill, in that a comparison of the eye movement strategies between expert surgeons and novices may show important differences that could be used in training. We conducted a preliminary study comparing the eye movements of 5 experts and 5 novices performing a one-handed aiming task on a computer-based laparoscopic surgery simulator. The performance results showed that experts were quicker and generally committed fewer errors than novices. We investigated eye movements as a possible factor for experts performing better than novices. The results from eye gaze analysis showed that novices needed more visual feedback of the tool position to complete the task than did experts. In addition, the experts tended to maintain eye gaze on the target while manipulating the tool, whereas novices were more varied in their behaviours. For example, we found that on some trials, novices tracked the movement of the tool until it reached the target.
Keywords: eye tracking, laparoscopic surgery, virtual training environment
Visual feature extraction via eye tracking for saliency driven 2D/3D registration BIBAKFull-Text 49-54
  Adrian James Chung; Fani Deligianni; Xiao-Peng Hu; Guang-Zhong Yang
This paper presents a new technique for extracting visual saliency from experimental eye tracking data. An eye-tracking system is employed to determine which features that a group of human observers considered to be salient when viewing a set of video images. With this information, a biologically inspired saliency map is derived by transforming each observed video image into a feature space representation. By using a feature normalisation process based on the relative abundance of visual features within the background image and those dwelled on eye tracking scan paths, features related to visual attention are determined. These features are then back projected to the image domain to determine spatial areas of interest for unseen video images. The strengths and weaknesses of the method are demonstrated with feature correspondence for 2D to 3D image registration of endoscopy videos with computed tomography data. The biologically derived saliency map is employed to provide an image similarity measure that forms the heart of the 2D/3D registration method. It is shown that by only processing selective regions of interest as determined by the saliency map, rendering overhead can be greatly reduced. Significant improvements in pose estimation efficiency can be achieved without apparent reduction in registration accuracy when compared to that of using a non-saliency based similarity measure.
Keywords: 2D/3D registration, eye tracking, image correlation, saliency
Eye tracking system model with easy calibration BIBAFull-Text 55
  Arantxa Villanueva; Rafael Cabeza; Sonia Porta
Calibration is one of the most tedious and often annoying aspects of many eye tracking systems. It normally consists in looking at several marks on a screen in order to collect enough data to modify the parameters of an adjustable model. Unfortunately this step is unavoidable if a competent tracking system is desired. Many efforts have been made to achieve more competent and improved eye tracking systems. Maybe the search for an accurate mathematical model is one of the least researched fields. The lack of a parametric description of the gaze estimation problem makes it difficult to find the most suitable model, and therefore generic expressions in calibration and tracking sessions are employed instead. In other words, a model based on parameters describing the elements involved in the tracking system would provide a stronger basis and robustness. The aim of this work is to build up a mathematical model totally based in realistic variables describing elements taking part in an eye tracking system employing the well known bright pupil technique i.e. user, camera, illumination and screen. The model is said to be defined when the expression relating the point the user is looking at with the extracted features of the image (glint position and center of the pupil) is found. The desired model would have to be simple, realistic, accurate and easy to calibrate.
Poster abstract: evaluation of hidden Markov models robustness in uncovering focus of visual attention from noisy eye-tracker data BIBFull-Text 56
  Neil Cooke; Martin Russell; Antje Meyer
Perceptual video compression with combined scene analysis and eye-gaze tracking BIBFull-Text 57
  Javed Khan; Oleg Komogortsev
Eye tracking off the shelf BIBAFull-Text 58
  Dan Witzner Hansen; David J. C. MacKay; John Paulin Hansen; Mads Nielsen
What if eye trackers could be downloaded and used immediately with standard cameras connected to a computer, without the need for an expert to setup the system? This has already the case for head trackers, so why not for eye trackers?
   Using components off-the-shelf (COTS) for camera-based eye tracking tasks has many advantages, but it certainly introduces several new problems as less assumptions on the system can be made. As a consequence of using COTS the price for eye tracking devices can be reduced while increasing the accessibility of these systems. Eye tracking based on COTS holds potential for a large number of possible applications such as in the games industry and eye typing [Majaranta and Räihä 2002]. Different cameras may be purchased depending on the need and the amount of money the user is willing to spend on the camera. In this framework it is not possible to use IR light sources and other novel engineered devices as they cannot be bought in a common hardware store. Very little control over the cameras and the geometry of the setup can be expected. The methods employed for eye tracking should therefore be able to handle changes in light conditions and image defocusing and scale changes [Hansen and Pece 2003]. On the same token pan-and-tilt cameras cannot be used, thus forcing such systems to be passive. Figure 1 shows a possible setup of a COTS-based eye tracker. When designing systems for the general public, it is unrealistic to assume that people are able to do camera calibration and make accurate setups of camera, monitor and user. Since little is known about the setup, would this then require a vast amount of calibration points needed for gaze estimation? That is, how many calibration points are really needed? Obviously the more calibration points are used the better the chances are to be able to infer the mapping from the image to gaze direction. It would even be possible to sample the entire function space provided sufficiently many calibration points are given. From the point of view of the users, a low number of calibration points is preferred as calibration may be considered as a tedious procedure. Systems that require many calibration points for every session are therefore not likely to succeed. It is also important to know the accuracy in gaze determination when using COTS to determine their applicability for various tasks.
Hardware-accelerated real-time simulation of arbitrary visual fields BIBAFull-Text 59
  Andrew T. Duchowski
Recent advancements in computer graphics hardware have made it possible to develop hardware-accelerated real-time imaging displays. This poster presents technical details of an OpenGL multitexturing approach for real-time simulation of arbitrary visual fields over a still image. Mipmapping facilitates in-hardware dyadic (power-of-two) degradation of the image to serve as the low-resolution periphery. Multitexture compositing provides a mechanism to combine the image's high-resolution pixels within a window (of arbitrary shape). The poster presents code examples to achieve gaze-contingent movement of the high-resolution window over a smoothly or coarsely degraded version of the image background as shown in Figure 1.To test the display rate of the multitexturing approach, the "runway" image (1024 x 512) of Figure 1 was shown in a 1280 x 1024 display window (sufficient to fill a 17'' flat panel). Image rendering was timed in code as the foveal Region Of Interest (ROI) was made to move continuously over the image (diagonally from the top-right corner to the bottom-left, maintaining the full ROI within the window). Sustained display rates (in frames per second) reported by the timer averaged 120 fps on three different platforms.
   The multitexturing display was successfully adapted to a gaze-contingent application using the Tobii eye tracker for real-time gaze measurement. The Tobii eye tracker can be configured in several ways, one of which is acting as a server for a (possibly remote) eye tracking client application. Communication between client and server occurs over TCP/IP. A Linux PC, used for most of the eye tracker code testing, was set up with dual monitors, as shown in Figure 1, with the Tobii server running on a Windows 2000 PC.
Focus of attention and pilot error BIBAFull-Text 60
  Eamonn K. S. Hanson
The evolution of cockpit automation is associated with an increased criticality of human error because missing, ignoring, or incorrectly processing even the smallest bit of relevant information can lead to an aircraft incident or accident occurrence. The most important factors associated with such occurrences are focus of attention and pilot error. Research performed at the National Aerospace Laboratory (NLR) has shown that changes in focus of attention can be measured via an eye tracking system (ASL 4000SU). The aim of this paper is to discuss how eye movements are used to indicate focus of attention, and how such information can be used to design new cockpit displays with decreased chances of pilot error.
An eye for an eye: a performance evaluation comparison of the LC technologies and Tobii eye trackers BIBFull-Text 61
  Daniel Cheng; Roel Vertegaal
Age differences in visual search for information on web pages BIBFull-Text 62
  Sheree Josephson; Michael E. Holmes
Coordination of component mental operations in a multiple-response task BIBAKFull-Text 63-70
  Shu-Chieh Wu; Roger W. Remington
Models of human performance typically focus on the mental components of task processing from discrete task trials. This approach neglects the advance planning of actions and overlapping of tasks characteristic of natural settings. The present research measures the joint timing of eye movements and manual responses in a typing-like task with the goal of extending models of discrete task performance to continuous domains. Following Pashler [1994] participants made separate choice responses to a series of five letters spread over a wide viewing area. Replicating Pashler's results, significant preview effects were found in both response time and eye movement data. Response to the first stimulus was delayed, with inter-response intervals for subsequent items rapid and flat across items. The eyes moved toward the next letter about 800 ms before the corresponding manual response (eye-hand span). Fixation dwell time was affected by stimulus luminance as well as difficulty of response mapping. The results suggest that fixation duration entails more than perceptual analyses. Implications of the results are discussed.
Keywords: attention, eye movements, eye-hand span, human performance modeling, mental operations
Frequency analysis of task evoked pupillary response and eye-movement BIBAKFull-Text 71-76
  Minoru Nakayama; Yasutaka Shimizu
This paper describes the influence of eye blinks on frequency analysis and power spectrum difference for task-evoked pupillography and eye-movement during an experiment which consisted of ocular following tasks and oral calculation tasks with three levels of task difficulty: control, 1x1,and 1x2 digit oral calculation.
   The compensation model for temporal pupil size based on MLP (multi layer perceptron) was trained to detect a blink and to estimate pupil size by using blinkless pupillary change and artificial blink patterns. The PSD (power spectrum density) measurements from the estimated pupillography during oral calculation tasks show significant differences, and the PSD increased with task difficulty in the area of 0.1-0.5Hz and 1.6-3.5Hz, as did the average pupil size.
   The eye-movement during blinks was corrected manually, to remove irregular eye-movements such as saccades. The CSD (cross spectrum density) was achieved from horizontal and vertical eye-movement coordinates. Significant differences in CSDs among experimental conditions were examined in the area of 0.6-1.5 Hz. These differences suggest that the task difficulty affects the relationship between horizontal and vertical eye-movement coordinates in the frequency domain.
Keywords: blink, eye-movement, frequency analysis, pupil, saccade
Mental imagery in problem solving: an eye tracking study BIBAKFull-Text 77-84
  Daesub Yoon; N. Hari Narayanan
Cognitive models and empirical studies of problem solving in visuo-spatial and causal domains suggest that problem solving tasks in such domains invoke cognitive processes involving mental animation and imagery. If these internal processes are externally manifested in the form of eye movements, such tasks present situations in which the trajectory of a user's visual attention can provide clues regarding his or her information needs to an Attentive User Interface [Vertegaal 2002]. In this paper, we briefly review research related to problem solving that involves mental imagery, and describe an experiment that looked for evidence and effects of an imagery strategy in problem solving. We eye-tracked 90 subjects solving two causal reasoning problems, one in which a diagram of the problem appeared on the stimulus display, and a second related problem that was posed on a blank display. Results indicated that 42% of the subjects employed mental imagery and visually scanned the display in a correspondingly systematic fashion. This suggests that information displays that respond to a user's visual attention trajectory, a kind of Attentive User Interface, are more likely to benefit this class of users.
Keywords: attentive user interface, empirical study, mental imagery, reactive information display
Resolving ambiguities of a gaze and speech interface BIBAKFull-Text 85-92
  Qiaohui Zhang; Atsumi Imamiya; Kentaro Go; Xiaoyang Mao
The recognition ambiguity of a recognition-based user interface is inevitable. Multimodal architecture should be an effective means to reduce the ambiguity, and contribute to error avoidance and recovery, compared with a unimodal one. But does the multimodal architecture always perform better than the unimode at any time? If not, when does it perform better than unimode, and when is it the optimum? Furthermore, how can modalities best be combined to gain the advantage of synergy? Little is known about these issues in the literature available. In this paper we try to give the answer through analyzing integration strategies for gaze and speech modalities, together with an evaluation experiment verifying these analyses. The approach involves studying the mutual correction cases and investigating when the mutual correction phenomena will occur. The goal of this study is to gain insights into integration strategies, and develop an optimum system to make error-prone recognition technologies perform at a more stable and robust level within a multimodal architecture.
Keywords: ambiguity, eye tracking, integration strategies, multimodal architecture, recognition errors, speech input
ECSGlasses and EyePliances: using attention to open sociable windows of interaction BIBAKFull-Text 93-100
  Jeffrey S. Shell; Roel Vertegaal; Daniel Cheng; Alexander W. Skaburskis; Changuk Sohn; A. James Stewart; Omar Aoudeh; Connor Dickie
We present ECSGlasses: wearable eye contact sensing glasses that detect human eye contact. ECSGlasses report eye contact to digital devices, appliances and EyePliances in the user's attention space. Devices use this attentional cue to engage in a more sociable process of turn taking with users. This has the potential to reduce inappropriate intrusions, and limit their disruptiveness. We describe new prototype systems, including the Attentive Messaging Service (AMS), the Attentive Hit Counter, the first person attentive camcorder eyeBlog, and an updated Attentive Cell Phone. We also discuss the potential of these devices to open new windows of interaction using attention as a communication modality. Further, we present a novel signal-encoding scheme to uniquely identify EyePliances and users wearing ECSGlasses in multiparty scenarios.
Keywords: attentive user interfaces, context-aware computing, eye contact sensing, eye tracking, ubiquitous computing
Auramirror: reflections on attention BIBAKFull-Text 101-108
  Alexander W. Skaburskis; Roel Vertegaal; Jeffrey S. Shell
As ubiquitous computing becomes more prevalent, greater consideration will have to be taken on how devices interrupt us and vie for our attention. This paper describes Auramirror, an interactive art piece that raises questions of how computers use our attention. By measuring attention and visualizing the results for the audience in real-time, Auramirror brings the subject matter to the forefront of the audience's consideration. Finally, some ways of using the Auramirror system to help in the design of attention sensitive devices are discussed.
Keywords: attentive user interfaces, computer vision, information visualization, media art, ubiquitous computing
Building a lightweight eyetracking headgear BIBAKFull-Text 109-114
  Jason S. Babcock; Jeff B. Pelz
Eyetracking systems that use video-based cameras to monitor the eye and scene can be made significantly smaller thanks to tiny micro-lens video cameras. Pupil detection algorithms are generally implemented in hardware, allowing for real-time eyetracking. However, it is likely that real-time eyetracking will soon be fully accomplished in software alone. This paper encourages an "open-source" approach to eyetracking by providing practical tips on building a lightweight eyetracker from commercially available micro-lens cameras and other parts. While the headgear described here can be used with any dark-pupil eyetracking controller, it also opens the door to open-source software solutions that could be developed by the eyetracking and image-processing communities. Such systems could be optimized without concern for real-time performance because the systems could be run offline.
Keywords: eyetracking, headgear, lightweight, wearable
A free-head, simple calibration, gaze tracking system that enables gaze-based interaction BIBAKFull-Text 115-122
  Takehiko Ohno; Naoki Mukawa
Human eye gaze is a strong candidate to create a new application area based on human-computer interaction. To implement a really practical gaze-based interaction system, gaze detection must be realized without placing any restriction on the user's behavior or comfort. This paper describes a gaze tracking system that offers freehead, simple personal calibration. It does not require the user wear anything on her head, and she can move her head freely. Personal calibration takes only a very short time; the user is asked to look at two markers on the screen. An experiment shows that the accuracy of the implemented system is about 1.0 degrees (view angle).
Keywords: corneal reflection method, free-head gaze detection, gaze tracking system, geometric eyeball model, human-computer interaction, personal calibration
Head movement estimation for wearable eye tracker BIBAKFull-Text 123-130
  Constantin A. Rothkopf; Jeff B. Pelz
In the study of eye movements in natural tasks, where subjects are able to freely move in their environment, it is desirable to capture a video of the surroundings of the subject not limited to a small field of view as obtained by the scene camera of an eye tracker. Moreover, recovering the head movements could give additional information about the type of eye movement that was carried out, the overall gaze change in world coordinates, and insight into high-order perceptual strategies. Algorithms for the classification of eye movements in such natural tasks could also benefit form the additional head movement data.
   We propose to use an omnidirectional vision sensor consisting of a small CCD video camera and a hyperbolic mirror. The camera is mounted on an ASL eye tracker and records an image sequence at 60 Hz. Several algorithms for the extraction of rotational motion from this image sequence were implemented and compared in their performance against the measurements of a Fasttrack magnetic tracking system. Using data from the eye tracker together with the data obtained by the omnidirectional image sensor, a new algorithm for the classification of different types of eye movements based on a Hidden-Markov-Model was developed.
Keywords: eye movement classification, head movement, natural task
Gaze typing compared with input by head and hand BIBAKFull-Text 131-138
  John Paulin Hansen; Kristian Tørning; Anders Sewerin Johansen; Kenji Itoh; Hirotaka Aoki
This paper investigates the usability of gaze-typing systems for disabled people in a broad perspective that takes into account the usage scenarios and the particular users that these systems benefit. Design goals for a gaze-typing system are identified: productivity above 25 words per minute, robust tracking, high availability, and support of multimodal input. A detailed investigation of the efficiency and user satisfaction with a Danish and a Japanese gaze-typing system compares it to head- and mouse (hand-) typing. We found gaze typing to be more erroneous than the other two modalities. Gaze typing was just as fast as head typing, and both were slower than mouse (hand-) typing. Possibilities for design improvements are discussed.
Keywords: alternative communication, assistive technology, computer input devices, eye mouse, eye tracking, eye typing, head mouse
Effects of feedback on eye typing with a short dwell time BIBAKFull-Text 139-146
  Päivi Majaranta; Anne Aula; Kari-Jouko Räihä
Eye typing provides means of communication especially for people with severe disabilities. Recent research indicates that the type of feedback impacts typing speed, error rate, and the user's need to switch her gaze between the on-screen keyboard and the typed text field. The current study focuses on the issues of feedback when a short dwell time (450 ms vs. 900 ms in a previous study) is used. Results show that the findings obtained using longer dwell times only partly apply for shorter dwell times. For example, with a short dwell time, spoken feedback results in slower text entry speed and double entry errors. A short dwell time requires sharp and clear feedback that supports the typing rhythm.
Keywords: disabled users, eye typing, feedback, text entry
The determinants of web page viewing behavior: an eye-tracking study BIBAKFull-Text 147-154
  Bing Pan; Helene A. Hembrooke; Geri K. Gay; Laura A. Granka; Matthew K. Feusner; Jill K. Newman
The World Wide Web has become a ubiquitous information source and communication channel. With such an extensive user population, it is imperative to understand how web users view different web pages. Based on an eye tracking study of 30 subjects on 22 web pages from 11 popular web sites, this research intends to explore the determinants of ocular behavior on a single web page: whether it is determined by individual differences of the subjects, different types of web sites, the order of web pages being viewed, or the task at hand. The results indicate that gender of subjects, the viewing order of a web page, and the interaction between page order and site type influences online ocular behavior. Task instruction did not significantly affect web viewing behavior. Scanpath analysis revealed that the complexity of web page design influences the degree of scanpath variation among different subjects on the same web page. The contributions and limitations of this research, and future research directions are discussed.
Keywords: eye tracking, individual differences, web page, world wide web