Showing papers on "Eye tracking published in 1999"

Manual and gaze input cascaded (MAGIC) pointing

Abstract: This work explores a new direction in utilizing eye gaze for computer input. Gaze tracking has long been considered as an alternative or potentially superior pointing method for computer input. We believe that many fundamental limitations exist with traditional gaze pointing. In particular, it is unnatural to overload a perceptual channel such as vision with a motor control task. We therefore propose an alternative approach, dubbed MAGIC (Manual And Gaze Input Cascaded) pointing. With such an approach, pointing appears to the user to be a manual task, used for fine manipulation and selection. However, a large portion of the cursor movement is eliminated by warping the cursor to the eye gaze area, which encompasses the target. Two specific MAGIC pointing techniques, one conservative and one liberal, were designed, analyzed, and implemented with an eye tracker we developed. They were then tested in a pilot study. This early- stage exploration showed that the MAGIC pointing techniques might offer many advantages, including reduced physical effort and fatigue as compared to traditional manual pointing, greater accuracy and naturalness than traditional gaze pointing, and possibly faster speed than manual pointing. The pros and cons of the two techniques are discussed in light of both performance data and subjective reports.

Effects of similarity and history on neural mechanisms of visual selection

Abstract: To investigate how the brain combines knowledge with visual processing to locate eye movement targets, we trained monkeys to search for a target defined by a conjunction of color and shape. On successful trials, neurons in the frontal eye field not only discriminated the target from distractors, but also discriminated distractors that shared a target feature as well as distractors that had been the search target during the previous session. Likewise, occasional errant saccades tended to direct gaze to distractors that either resembled the current target or had been the previous target. These findings show that the frontal eye field is involved in visual and not just motor selection and that visual selection is influenced by long-term priming. The data support the hypothesis that visual selection can be accomplished by parallel processing of objects based on their elementary features.

Parieto-frontal coding of reaching: an integrated framework

Abstract: In the last few years, anatomical and physiological studies have provided new insights into the organization of the parieto-frontal network underlying visually guided arm-reaching movements in at least three domains. (1) Network architecture. It has been shown that the different classes of neurons encoding information relevant to reaching are not confined within individual cortical areas, but are common to different areas, which are generally linked by reciprocal association connections. (2) Representation of information. There is evidence suggesting that reach-related populations of neurons do not encode relevant parameters within pure sensory or motor "reference frames", but rather combine them within hybrid dimensions. (3) Visuomotor transformation. It has been proposed that the computation of motor commands for reaching occurs as a simultaneous recruitment of discrete populations of neurons sharing similar properties in different cortical areas, rather than as a serial process from vision to movement, engaging different areas at different times. The goal of this paper was to link experimental (neurophysiological and neuroanatomical) and computational aspects within an integrated framework to illustrate how different neuronal populations in the parieto-frontal network operate a collective and distributed computation for reaching. In this framework, all dynamic (tuning, combinatorial, computational) properties of units are determined by their location relative to three main functional axes of the network, the visual-to-somatic, position-direction, and sensory-motor axis. The visual-to-somatic axis is defined by gradients of activity symmetrical to the central sulcus and distributed over both frontal and parietal cortices. At least four sets of reach-related signals (retinal, gaze, arm position/movement direction, muscle output) are represented along this axis. This architecture defines informational domains where neurons combine different inputs. The position-direction axis is identified by the regular distribution of information over large populations of neurons processing both positional and directional signals (concerning the arm, gaze, visual stimuli, etc.) Therefore, the activity of gaze- and arm-related neurons can represent virtual three-dimensional (3D) pathways for gaze shifts or hand movement. Virtual 3D pathways are thus defined by a combination of directional and positional information. The sensory-motor axis is defined by neurons displaying different temporal relationships with the different reach-related signals, such as target presentation, preparation for intended arm movement, onset of movements, etc. These properties reflect the computation performed by local networks, which are formed by two types of processing units: matching and condition units. Matching units relate different neural representations of virtual 3D pathways for gaze or hand, and can predict motor commands and their sensory consequences. Depending on the units involved, different matching operations can be learned in the network, resulting in the acquisition of different visuo-motor transformations, such as those underlying reaching to foveated targets, reaching to extrafoveal targets, and visual tracking of hand movement trajectory. Condition units link these matching operations to reinforcement contingencies and therefore can shape the collective neural recruitment along the three axes of the network. This will result in a progressive match of retinal, gaze, arm, and muscle signals suitable for moving the hand toward the target.

Eye tracking the visual search of click-down menus

Abstract: Click-down (or pull-down) menus have long been a key component of graphical user interfaces, yet we know surprisingly little about how users actually interact with such menus. Nilsens [8] study on menu selection has led to the development of a number of models of how users perform the task [6, 21. However, the validity of these models has not been empirically assessed with respect to eye movements (though [l] presents some interesting data that bear on these models). The present study is an attempt to provide data that can help refine our understanding of how users interact with such menus.

Robust real-time visual tracking using a 2D-3D model-based approach

Abstract: We present an original method for tracking, in an image sequence, complex objects which can be approximately modeled by a polyhedral shape. The approach relies on the estimation of the 2D object image motion along with the computation of the 3D object pose. The proposed method fulfills real-time constraints along with reliability and robustness requirements. Real tracking experiments and results concerning a visual servoing positioning task are presented.

Vision-based eye-gaze tracking for human computer interface

Abstract: Eye-gaze is an input mode which has the potential for an efficient computer interface. Eye movement has been the focus of research in this area. Non-intrusive eye-gaze tracking that allows slight head movement is addressed in this paper. A small 2D mark is employed as a reference to compensate for this movement. The iris center has been chosen for the purposes of measuring eye movement. The gaze point is estimated after acquiring the eye movement data. Preliminary experimental results are given through a screen pointing application.

Eye Movements in Reading

Abstract: The last 25 years have seen impressive advances in reading research, based on eye movement recording, with respect to both theory and methodology. An important milestone at the beginning of recent developments was the work of McConkie and Rayner on the perceptual span (see summaries in Rayner 1984; McConkie 1983). Here, for the first time, registration devices and computers were combined in a way that allowed to introduce a new dimension into reading research: the manipulation of the useful field of view under dynamic conditions.

The Emotion Mouse

Abstract: One goal of human computer interaction (HCI) is to make an adaptive, smart computer system. This type of project could possibly include gesture recognition, facial recognition, eye tracking, speech recognition, etc. Another non-invasive way to obtain information about a person is through touch. People use their computers to obtain, store and manipulate data using their computer. In order to start creating smart computers, the computer must start gaining information about the user.

Method and apparatus for eye tracking and monitoring pupil dilation to evaluate cognitive activity

Abstract: Method and apparatus for correlating pupillary response to the cognitive activity of a subject undergoing an evaluation of cognitive activity during a task which involves monitoring and recording the point of gaze and pupillary response of the subject to the task, subjecting the recorded pupillary response to wavelet analysis in order to identify any dilation reflex of the subject's pupil during the task, and assigning a pupillary response value to the result of the wavelet analysis.

Eye and gaze tracking for visually controlled interactive stereoscopic displays

Abstract: We present a video-based, contact-free measurement system which allows combined tracking of the subject's eye positions and the gaze direction in near real time. This system will be integrated into a new kind of autostereoscopic display which supports the natural link between accommodation and convergence of human vision, reproduces the limited depth of focus of human vision and shows comfortable, hologram-like scenes with motion parallax to subjects.

System and method for controlling host system interface with user point-of-interest data

Abstract: A system and method are disclosed for a user interface control that utilizes one or more graphical objects (“comets”), which can be operated solely by the eye gaze of a user. The disclosed system and method enables users to access and control, for example, computer displays without use of hands, voice or other forms of input. Each comet may be implemented as an animated graphic object that is mapped to one or more computer functions (a command set) by a computer or software application programmer. A computer-based system may create one or more comets on a display device and place them in motion. Eye tracking data may be collected over a period of time based on the detected point-of-gaze of a user's eye. If the user is determined to be visually tacking a particular comet, the comet will become selected and the computer or host system may execute the command set that has been mapped to the selected comet. The disclosed system and method may also be adapted to determine a user's point-of-interest based on the movement of an input device (such as a conventional mouse, trackball, data glove, etc.) and to select a comet based on a correspondence between the movement of the comet and the movement of the input device.

Keeping an eye on gestures: Visual perception of gestures in face-to-face communication

Abstract: Since listeners usually look at the speaker's face, gestural information has to be absorbed through peripheral visual perception. In the literature, it has been suggested that listeners look at gestures under certain circumstances: 1) when the articulation of the gesture is peripheral; 2) when the speech channel is insufficient for comprehension; and 3) when the speaker him- or herself indicates that the gesture is worthy of attention. The research here reported employs eye tracking techniques to study the perception of gestures in face-to-face interaction. The improved control over the listener's visual channel allows us to test the validity of the above claims. We present preliminary findings substantiating claims 1 and 3, and relate them to theoretical proposals in the literature and to the issue of how visual and cognitive attention are related.

Method for inferring mental states from eye movements

Abstract: A computer-implemented method infers mental states of a person from eye movements of the person. The method includes identifying elementary features of eye tracker data, such as fixations and saccades, and recognizing from the elementary features a plurality of eye-movement patterns. Each eye-movement pattern is recognized by comparing the elementary features with a predetermined eye-movement pattern template. A given eye-movement pattern is recognized if the elementary features satisfy a set of criteria associated with the template for that eye-movement pattern. The method further includes the step of recognizing from the eye-movement patterns a plurality of eye-behavior patterns corresponding to the mental states of the person. Because high level mental states of the user are determined in real time, the method provides the basis for reliably determining when a user intends to select a target.

Incremental Focus of Attention for Robust Vision-Based Tracking

Abstract: We present the Incremental Focus of Attention (IFA) architecture for robust, adaptive, real-time motion tracking. IFA systems combine several visual search and vision-based tracking algorithms into a layered hierarchy. The architecture controls the transitions between layers and executes algorithms appropriate to the visual environment at hand: When conditions are good, tracking is accurate and precises as conditions deteriorate, more robust, yet less accurate algorithms take overs when tracking is lost altogether, layers cooperate to perform a rapid search for the target and continue tracking. Implemented IFA systems are extremely robust to most common types of temporary visual disturbances. They resist minor visual perturbances and recover quickly after full occlusions, illumination changes, major distractions, and target disappearances. Analysis of the algorithm‘s recovery times are supported by simulation results and experiments on real data. In particular, examples show that recovery times after lost tracking depend primarily on the number of objects visually similar to the target in the field of view.

Bayesian Modality Fusion: Probabilistic Integration of Multiple Vision Algorithms for Head Tracking

Abstract: We describe a head-tracking system that harnesses Bayesian modality fusion, a technique for integrating the analyses of multiple visual tracking algorithms within a probabilistic framework. At the heart of the approach is a Bayesian network model that includes random variables that serve as context-sensitive indicators of reliability of the different tracking algorithms. Parameters of the Bayesian model are learned from data in an offline training phase using ground-truth data from a Polhemus tracking device. In our implementation for a real-time head tracking task, algorithms centering on color, motion, and background subtraction modalities are fused into a single estimate of head position in an image. Results demonstrate the effectiveness of Bayesian modality fusion in environments undergoing a variety of visual perturbances.

Keeping an eye for HCI

Abstract: Advanced human-computer interaction (HCI) techniques are required to enhance current computer interfaces. In this paper, we present an eye gaze tracking system based on a robust low-cost real-time pupil detector, and we describe some eye-aware applications that are being developed to enhance HCI. Images of pupils are segmented using an active lighting scheme that exploits very particular properties of eyes. Once the pupil is detected, its center is tracked, along with the corneal reflection (CR) generated by the light sources. Assuming little head motion, the eye gaze direction is computed based on the vector between the centers of the CR and the pupil, after a brief calibration procedure. Other information, such as pupil size and blink rate, can also be made available. The current prototype runs at frame rate, providing 30 samples of the gaze position per second to gaze-aware applications, such as advanced pointing and selection mechanisms.

MR-eyetracker: a new method for eye movement recording in functional magnetic resonance imaging.

Abstract: We present a method for recording saccadic and pursuit eye movements in the magnetic resonance tomograph designed for visual functional magnetic resonance imaging (fMRI) experiments. To reliably classify brain areas as pursuit or saccade related it is important to carefully measure the actual eye movements. For this purpose, infrared light, created outside the scanner by light-emitting diodes (LEDs), is guided via optic fibers into the head coil and onto the eye of the subject. Two additional fiber optical cables pick up the light reflected by the iris. The illuminating and detecting cables are mounted in a plastic eyepiece that is manually lowered to the level of the eye. By means of differential amplification, we obtain a signal that covaries with the horizontal position of the eye. Calibration of eye position within the scanner yields an estimate of eye position with a resolution of 0.2° at a sampling rate of 1000 Hz. Experiments are presented that employ echoplanar imaging with 12 image planes through visual, parietal and frontal cortex while subjects performed saccadic and pursuit eye movements. The distribution of BOLD (blood oxygen level dependent) responses is shown to depend on the type of eye movement performed. Our method yields high temporal and spatial resolution of the horizontal component of eye movements during fMRI scanning. Since the signal is purely optical, there is no interaction between the eye movement signals and the echoplanar images. This reasonably priced eye tracker can be used to control eye position and monitor eye movements during fMRI.

Method for presenting high level interpretations of eye tracking data correlated to saved display images

Abstract: A software program stores during a recording session eye-tracking data and all other communication device activities of a test person that self-controlled confronts her/himself with display scenarios or virtual pages. The display scenarios are stored simultaneously either: 1. after a predetermined elapse time interval, 2. after recognizing a raised attention level of the test person, 3. after a positive result of a scrolling detection process. In a consecutive processing cycle, the software program utilizes an eye interpretation engine to derive high level informations and visualizes them superimposed on the correlated image scenarios.

Eye Movements and a Rule for Perceiving Direction of Heading

Abstract: (1999). Eye Movements and a Rule for Perceiving Direction of Heading. Ecological Psychology: Vol. 11, No. 3, pp. 233-248.

Eye tracker for refractive surgery

Abstract: A method of determining the position or attitude of an eye, including the steps of directing a plurality of eye-safe light beam components onto the eye, said components defining an area of incidence on the eye substantially larger than the pupil; receiving an image of light thereafter reflected by the eye; analysing the image by identifying which of the light beam components produces a bright eye reflection in said image; and determining the position or attitude of the eye by further analysing the image on the basis of said identification.

The hunt for usability: tracking eye movements

Abstract: Usability testing methods have not changed significantly since the origins of the practice. Usability studies typically address human performance at a readily observable task-level, including measures like time to complete a task, percentage of participants succeeding, type and number of errors, and subjective ratings of ease of use [3]. Certain types of questions are difficult to answer efficiently with these techniques. Imagine, for example, that we observe users spending longer than expected looking at a particular dialog of a software application or web page without making the appropriate selection to complete the task. Participants often have difficulty reporting their behavior and the experimenter is clueless about what went wrong. Is it because the user is overlooking the control? Is the user distracted by another element in the interface -- perhaps an animated graphic? Is the user seeing the control, but failing to comprehend its meaning? Different answers to these questions would clearly lead to different recommendations. If overlooking the control is a problem, increasing its salience is appropriate. If confusion of the control's function is a problem, changing the graphic or text label may be appropriate. If distraction is a problem, decreasing the salience of other stimuli may help. Without answers to these questions, design recommendations have to be implemented by trial and error. Recording the fixation pattern of the participant's eyes can offer additional information to help answer these questions. While this concept is not new, it has been confined primarily to military aircraft cockpit issues [2,4]. Only recently has eye tracking technology advanced to make it practical in the broader usability community. Usability studies of human-computer systems that have included eye tracking, e.g., [1] are beginning to show benefits of these techniques. However, important challenges remain.

An Information-Theoretic Framework for Understanding Saccadic Eye Movements

Abstract: In this paper, we propose that information maximization can provide a unified framework for understanding saccadic eye movements. In this framework, the mutual information among the cortical representations of the retinal image, the priors constructed from our long term visual experience, and a dynamic short-term internal representation constructed from recent saccades provides a map for guiding eye navigation. By directing the eyes to locations of maximum complexity in neuronal ensemble responses at each step, the automatic saccadic eye movement system greedily collects information about the external world, while modifying the neural representations in the process. This framework attempts to connect several psychological phenomena, such as pop-out and inhibition of return, to long term visual experience and short term working memory. It also provides an interesting perspective on contextual computation and formation of neural representation in the visual system.

Variable-Resolution Displays for Visual Communication and Simulation

Abstract: The spatial resolution of the human visual system decreases as a function of angular distance from the direction of gaze. This fact can be exploited in various applications to increase image compression, to increase image processing speed, and to decrease access time for image data. This paper describes a multiresolution pyramid method for creating variable resolution displays in real time using general purpose computers. The location of the high resolution region(s) can be dynamically controlled by the user with a pointing device (e.g., a mouse or an eye tracker) or by an algorithm. Our method has a number of advantages: high computational speed and efficiency, smooth artifact-free variable resolution, and compatibility with other image processing software/hardware. Applications to video communications (MPEG) and graphic simulation are described.

Manipulation of Video Eye Gaze and Head Orientation for Video Teleconferencing

Abstract: Many desktop videoconferencing systems are ineffective due to deficiencies in gaze awareness and sense of spatial relationship. Gaze awareness and spatial relationships can be restored by software if heads and eyes can be tracked in video, and then graphically manipulated. We discuss graphics algorithms for manipulating eye gaze and head orientation. Our system takes video input annotated with head and eye information and outputs an adjusted video with appropriate gaze and head orientation. Initial results demonstrate the viability and usefulness of such a system.

Effects of dual task demands on the accuracy of smooth pursuit eye movements

Abstract: The effect of attention allocation on smooth pursuit eye movements (SPEM) was investigated. Eye movements were electrooculographically recorded in 27 healthy subjects who tracked a visual target that moved horizontally with constant or unpredictably varying velocity. In some trials, subjects performed additional auditory discrimination tasks varying in difficulty. Pursuit error decreased when attention was divided between both tasks. The pattern of results is incompatible with the assumption made in previous research that attention enhancement improves SPEM accuracy. Rather, ocular smooth pursuit appears to be executed in the automatic mode, although intentional and selective processes must contribute. Moreover, controlled attention directed to the tracking task interfered with smooth pursuit. A reinterpretation of earlier studies in which visual monitoring tasks were used to improve eye tracking is needed.