Showing papers on "Eye tracking published in 1991"

The use of eye movements in human-computer interaction techniques: what you look at is what you get

Abstract: In seeking hitherto-unused methods by which users and computers can comrnumcate, we investigate the usefulness of eye movements as a fast and convenient auxiliary user-to-computer communication mode. The barrier to exploiting this medium has not been eye-tracking technology but the study of interaction techniques that incorporate eye movements mto the usercomputer dialogue in a natural and unobtrusive way This paper discusses some of the human factors and technical considerations that arise in trying to use eye movements as an input medium, describes our approach and the first eye movement-based interaction techniques that we have devised and implemented in our laboratory, and reports our experiences and observa tions on them.

Eye tracking method and apparatus

Abstract: In applications where it is desired to determine the locations of image features, such as eye monitoring to determine the direction that a person is gazing, determining the point at which he is gazing, or measuring the motions of his eye using a camera to capture an optical image of the eye and image processing to extract information about the eye's gaze point and/or orientation, there is provided a method and apparatus for precise location of image features such as edge coordinates between the pupil anc iris of the eye and of the center coordinates of light reflections off the cornea of the eye.

Evolution of the eye and visual system

Abstract: Evolution of visual behaviour in animals evolution of the eye - from the light sensitive cephalic organ of nemertoid worms to the vertebrate eye the eye of Copelia - tectile and visual scanning as primitive means of form perception the response to light in prokaryotes and protozoa evolution of the compond eye and visual systems of arthropods evolution of the eye and visual system of molluscs evolution of visual pigments and photoreceptors evolution of the vertebrate retina (including - phylogenetic differences in the morphology and function of retinal ganglion and other nerve cells and their possible relationship to differences in visual behaviour) morphological and functional evolution of pretectum, dorsal thalamus and visual cortex nucleus isthmi or parabigeminal nucleus nucleus rotundus and pulvinar visual tracking and the cerebral control of gaze response to visual shadows. Lateral inhibition and contrast sensitivity and the subsequent development of movement and directional sensitivity the detection of visual form evolution of colour vision evolution of depth perception (binocular vision and stereopsis) the phylogenetic segregation of movement, colour and pattern systems within the brain.

Clinical, neuropsychological, and brain structural correlates of smooth-pursuit eye tracking performance in chronic schizophrenia.

Abstract: The relation of smooth-pursuit eye tracking dysfunction to neuropsychological performance, brain structural anomalies, and clinical state was examined in a sample of 61 patients with chronic schizophrenia. No association was found between impaired pursuit oculomotion and measures of chronicity or clinical state. Likewise, no association emerged between eye-tracking integrity and brain structural anomalies. Patients with dysfunctional eye tracking were more likely to have impaired performance on tests that assess frontal lobe functioning. In addition, negative symptoms and a relative absence of positive symptoms. Because negative symptoms are often found among patients with frontal lobe impairment, their association with abnormal eye tracking provides converging support for the hypothesis that the cortical locus of deviant smooth-pursuit eye tracking is in the frontal lobes.

Analysis of eye tracking movements using innovations generated by a Kalman filter.

Abstract: A simple but efficient algorithm has been developed for computer analysis of eye tracking movements. The program separates smooth pursuit and saccadic eye movements. Separation of the two components is achieved using a two-step process of saccade detection. First, an AR model of the velocity of the smooth component is identified and used to determine a Kalman filter. Secondly the innovation sequence generated by this filter allows saccade detection. The precise beginning and end of each saccade are found using a Hinkley algorithm. Examples are given of analysis procedure for eye tracking of a random moving target. The method proved to be highly reliable and could be easily extended to other eye movements such as nystagmus.

Measuring three dimensions of eye movement in dynamic situations by means of videooculography.

Abstract: A primary function of the vestibular system is the stabilisation of the eye during head movement. Consequently, evaluation of reflex eye movements represents an essential means to both clinical diagnosis and researching of the vestibular function. Movements in the eye can be resolved into three orthogonal components, i.e. horizontal, vertical and torsional. As an improvement on most current techniques, which provide only measurement of the horizontal and vertical components, videooculography (VOG) facilitates non-invasive measurement of all three of the defined components. To date, only the scleral coil technique, which involves the semi-invasive placement of coil rings onto the bulbi, yields a continuous measure of eye torsion. Employment of suitable solid-state devices permit the integration of a compact, high resolution video recording system. In the basic configuration, eye movements can be observed and simultaneously recorded for later analysis or documentation. The video images of the eye are obtained by means of a miniaturised CCD video sensor mounted on a light-occluding mask. Image processing of the acquired video images determines horizontal and vertical coordinates of eye position online. Ocular torsion, as reflected by the rotation of the natural iris, is measured for each video frame. The VOG algorithm has been implemented on a PC based workstation, which permits online observation, recording and evaluation of eye movements. In addition, the technique has found clinical application as a portable eye-movement observation and recording system, allowing bedside examination and recording of transient symptoms. Preliminary results from various studies, including the objective evaluation of positional nystagmus (BPPN), are presented.

Eye monitor: microcomputer-based instrument uses an internal mode to track the eye

Abstract: An eye monitor whose design is inspired by the human visual system is presented. The monitor incorporates an internal representation or model of what the eye looks like to a video camera. The system can measure the position of the eyes and the size of the pupil in the presence of interfering noise and in patients wearing eyeglasses or contact lenses, and it tolerates defocusing due to small movements in depth by the patient. The system makes real-time correction for head and eye movements while measuring pupillary responses to controlled light stimuli. The design and software and hardware components are described, and some applications are noted. Its use for early clinical detection of visual diseases by objectively measuring pupillary responses to carefully controlled light stimuli is examined as an example. Some general observations about using computers in medical measurements are made. >

Correlation of Wisconsin Card Sorting Test performance with eye tracking in schizophrenia.

Abstract: The authors studied the relationship between performance on the Wisconsin Card Sorting Test and on the Trailmaking-B test and measures of smooth pursuit eye movements in 12 patients with chronic schizophrenia and 12 normal volunteers. They found that performance on the Wisconsin Card Sorting Test was significantly correlated with measures of smooth pursuit eye movements in schizophrenic patients but not in normal subjects. Trailmaking-B scores, however, were unrelated to smooth pursuit eye movements in either group. (AmJ Psychiatry1991; 148:1580-1582)

An Eye Scan Analysis of Accessing Product Warning Information

Abstract: Eye tracking procedures were employed to study eye scan patterns of subjects searching for warning messages in product labels. Thirty-eight alcoholic beverage labels were constructed, 24 of which contained a warning. For each label, subjects indicated whether or not it contained a warning. Salience of the warning was manipulated by the presence or absence of four features which appeared individually or in combination. The features were a pictorial, an icon, color and a border. Of particular interest was the ability to decompose the total time it takes to find the warning in two components: location time and decision time. Location refers to the time it takes to find the area where the warning is, and decision refers to the time it takes to determine if the given information is a warning, as well as the time to make an overt response. The results show that the singular addition of a pictorial, an icon, color or a border did not produce a significant improvement in total time or in location time relative to...

Eye-head movement coordination: vestibulo-ocular reflex suppression with head-fixed target fixation

Abstract: To maintain clear vision, the images on the retina must remain reasonably stable. Head movements are generally dealt with successfully by counter-rotation of the eyes induced by the combined actions of the vestibulo-ocular reflex (VOR) and the optokinetic reflex. A problem of importance relates to the value of the so-called intrinsic gain of the VOR (VORG) in man, and how this gain is modulated to provide appropriate eye movements. We have studied these problems in two situations: 1. fixation of a stationary object of the visual space while the head moves; 2. fixation of an object moving with the head. These two situations were compared to a basic condition in which no visual target was allowed in order to induce "pure" VOR. Eye movements were recorded in seated subjects during stationary sinusoidal and transient rotations around the vertical axis. Subjects were in total darkness (DARK condition) and involved in mental arithmetic. Alternatively, they were provided with a small foveal target, either fixed with respect to earth (earth-fixed target: EFT condition), or moving with them (chair-fixed-target: CFT condition). The stationary rotation experiment was used as baseline for the ensuing experiment and yielded control data in agreement with the literature. In all 3 visual conditions, typical responses to transient rotations were rigorously identical during the first 200 ms. They showed, sequentially, a 16-ms delay of the eye behind the head and a rapid increase in eye velocity during 75 to 80 ms, after which the average VORG was 0.9 +/- 0.15. During the following 50 to 100 ms, the gain remained around 0.9 in all three conditions. Beyond 200 ms, the VORG remained around 0.9 in DARK and increased slowly towards 1 or decreased towards zero in the EFT and CFT conditions, respectively. The time-course of the later events suggests that visual tracking mechanisms came into play to reduce retinal slip through smooth pursuit, and position error through saccades. Our data also show that in total darkness VORG is set to 0.9 in man. Lower values reported in the literature essentially reflect predictive properties of the vestibulo-ocular mechanism, particularly evident when the input signal is a sinewave.

Using Eye Movements to Classify Search Strategies

Abstract: This paper describes a study which employed eye tracking to investigate visually searching lists. An experiment was designed to test if “cognitive style” influences search strategies. We examined the search patterns of subjects as they viewed lists of sorted and randomly ordered columns. We found that cognitive style was a good predictor of the scanning strategies of ordered lists. For the unordered lists, efficient, systematic searching was performed by college students but not by high school students.

The interaction of hand vibration with oculomanual coordination in pursuit tracking.

Abstract: The effects of high frequency hand vibration (150 Hz) on simultaneous ocular and manual tracking performances were investigated in trained human subjects. First, a zero-order pursuit tracking task was performed with and without direct visual control of the hand. Second, eye tracking of an imaginary target linked to the hand was also performed. The results show that hand vibration significantly alters eye and hand tracking performances when the hand is out of sight. However, when the hand is placed in the visual field, tracking performances are less affected by vibration. Visual cues on limb segments may compensate to some extent for the vibration-induced alteration of proprioceptive information otherwise used to control movements. Eye movements are altered during vibration while the subject is tracking or fixating an imaginary target attached to the hand. These findings explicitly show that hand vibration can perturb oculo-manual coordination control. The present results imply that vibration-induced activity of somesthetic mechanoreceptors is likely to contribute to oculomanual coordination alteration and tracking decrement in vibratory environments. Furthermore, direct visual control of the hand and/or arm may be of particular interest in manipulation tasks executed under vibration. Language: en

Oculomotor control and cognitive processes : normal and pathological aspects

Abstract: Neural networks applied to the oculomotor system (D.A. Robinson). Eye movements in neurological diagnosis: Huntington's disease and congenital nystagmus (D.S. Zee). Neurophysiology of Eye Movements. Localization of targets in humans: the role of ocular muscle proprioception (D. Nommay et al). Effects of severance of the vestibular commissural pathway on the neural integrator of the oculomotor system in cat (E. Godaux, G. Cheron). Representation of three-dimensional eye movements in the cerebellar flocculus of the rabbit (J. van der Steen et al). Effects of floccular injections of noradrenergic agonists and antagonists on adaptive changes in the VOR gain (J. van Neerven et al). The Control of Eye Movements. Human vestibuloocular reflex (VOR) and vestibular velocity storage as influenced by optokinetic stimuli (E. Koenig et al). Vertical gaze stability in cat: otolithic contribution (V.E. Pettorossi et al). Post-rotational nystagmus suppression by the presentation of a single visual target in cat and man (G. Magenes et al). Adaptive mechanisms in the monkey saccadic system (P. Inchingolo et al). Human express saccades: catch trails influence the probability of their occurrence (M. Juttner, W. Wolf). Eye-Head Coordination. Adaptation of eye and head movements to reduced peripheral vision (G.M. Gauthier et al). Coupled and dissociated modes of eye-head coordination in humans to flashed visual target (S. Ron, A. Berthoz). Superior colliculus and feedback control of gaze shift in the head-free cat (D. Pelisson et al). Strategies of eye-head coordination (R. Schmid, D. Zambarbieri). Eye Movements in Pathology. Sensory and motor aspects of congenital nystagmus (R.V. Abadi et al). Head-shaking nystagmus - A clinical tool to detect peripheral and central vestibular asymmetries (M. Fetter et al). Saccadic and smooth pursuit eye movements in olivo-ponto-cerebellar atrophies (M. Spanio et al). Slow eye movement abnormalities in Wallenberg's lateral medullary syndrome (W. Waespe). Eye tracking dysfunctions in schizophrenic patients - Why is there no neuroleptic side-effect? (N. Hock et al). Eye Movements and Cognitive Processes. A mathematical analysis of the convenient viewing position hypothesis and its components (M. Brysbaert, G. d'Ydewalle). Is there an optimal landing position in words during reading of texts? (F. Vitu, J.K. O'Regan). Processing of prepositions as reflected by gaze durations (A. Wilbertz et al). The latency of saccadic eye movements to texture-defined stimuli (H. Deubel, H. Frank). Does thinking aloud influence the structure of cognitive processes? (U. Lass et al). Eye movements in visual search: a test of the limited cognitive effort hypothesis and an analysis of the search operating characteristic (A.M. Jacobs). Applied Research. Colour, effective contrast and search performance (J.L. Barbur et al). Video-oculography - An alternative method for measurement of three-dimensional eye movements (A.H. Clarke et al).

Smooth pursuit eye tracking dysfunction in schizophrenia: subcortical implications.

Abstract: The study of smooth pursuit eye tracking behavior in schizophrenics has occupied a prominent position in the search for biological correlates of this mental illness for nearly 20 years. During this time, impairments in this behavior have been shown to be a most robust finding in these patients. Attempts to further characterize the basis for this dysfunction have emphasized the role of cortical--particularly frontal--processes in both the symptomatology of schizophrenia and the eye tracking disturbance. In the present paper, arguments are made in support of a subcortical contribution to smooth pursuit eye tracking dysfunction in schizophrenia. Supporting data include new observations of cortical EEG variations in association with pursuit tracking disruptions, and a review of recent data indicating visual-vestibular and cerebellar-vestibular influences on the tracking disturbances in these patients. On the basis of such data, it is concluded that it is highly unlikely that a single mechanism or process is exclusively responsible for impaired pursuit tracking in schizophrenics, and that there are data to support both cortical and subcortical contributions to this dysfunction.

Non-invasive eye-gaze position detecting method used on man/machine interface for the disabled

Abstract: A novel eye-gaze detection method overcoming the weaknesses of previous methods is proposed. This system utilizes a video-based technique. The eye, illuminated by low-level infrared (IR) light, is scanned by a charge-coupled device (CCD) camera with an IR pass filter. IR light enters the pupil, is reflected off the retina and comes out through the pupil. The pupil image appears as a larger half-lighted disc against a darker background, called the bright eye. Its position moves in the camera field, following the motion of the eye. A fraction of the IR light is reflected off the corneal surface. This appears in the camera field as a small, intense area called the glint. The method does not need any sensors attached to the user's face, and allows free head movement. >

Analysis Of Two Video Eye Tracking Algorithms

Abstract: We are using a video tracking system for recording eye movements during vestibular experiments. The data are taken by a helmet mounted camera using infrared illumination. The measurement system need not run in real time but it must be tolerant to partial eye closings and other obstructions such as Purkinje spots. Two algorithms, each with its own advantages and disadvantages, have been adapted to our program shell which runs on the Macintosh IIx series computer. The algorithm requiring the least computation is a least squares (LS) fit of partial pupil edge data to a circular arch. It is vulnerable to out liers and biases due to finite edge width and asymmetries. A maximum likelihood method is computationally intense but is robust under many conditions of image obstruction which sends the LS algorithm astray.

Image data compressing processor

Abstract: PURPOSE:To simultaneously execute the maintenance of a high picture quality and the curtailment of the data quantity without a special decision or operation executed by an observer by deriving the observation time in every partial area of a visible image reproduced and displayed on a display means by monitoring the observer's eye by an eye camera, and varying the data compression processing in accordance with its observation time. CONSTITUTION:The processor is constituted of a display means 1, a data compression processing means 2, an eye tracking camera 3, and an observation time accumulating means 4. In this state, an observer's eye for observing an image displayed on the display means 1 is tracked by the eye tracking camera (eye camera) 3, an observation time in every partial area is derived, and based on length of the observation time in every partial area, a data compression processing is performed to image data for showing an image so that the area in which the observation time is short becomes high compressibility. In such a way, by compressing the image data to high compressibility without a special decision or operation executed by the observer, a fact that the data quantity is curtailed, and a fact that deterioration of the image is suppressed to the minimum are allowed coexist with each other.

Rapid Nonconjugate Adaptation of Vertical Voluntary Pursuit Eye Movements

Abstract: : The precise yoking of the two eyes during vertical eye movements is normally preserved throughout life. This preservation is due in part to adaptive processes that adjust the relative neural innervations sent to each eye's extraocular muscles (nonconjugate adaptation). This behavioral study investigates adaptive processes that maintain conjugacy along the vertical meridian during three types of ocular motor behavior: voluntary pursuit, saccade, and steady fixation. Binocular yoking was quantified by binocular recordings of vertical eye position (dual-Purkinje eye tracker) while vertical eye movements were monocularly stimulated. Properties of nonconjugate adaptive processes were inferred from changes in pre- and post-adaptation binocular yoking.

Recurrent Eye Tracking Network Using a Distributed Representation of Image Motion

Abstract: We have constructed a recurrent network that stabilizes images of a moving object on the retina of a simulated eye. The structure of the network was motivated by the organization of the primate visual target tracking system. The basic components of a complete target tracking system were simulated, including visual processing, sensory-motor interface, and motor control. Our model is simpler in structure, function and performance than the primate system, but many of the complexities inherent in a complete system are present.

Eye-slaved pointing system for tele-operator control

Abstract: The human eye ts potentially an ideal input device for teleoperator control applications due to the innate ability of the oculomotor system to rapidly shift the line of gaze in response to changing visual stimuli. An electro-optic system has been developed to automatically compute the eye position of a teleoperator and feedback onto the video display a reticle slaved to his eye movements. This ye slaved pointing system allows an operator with mimmal hand/eye coordina tion skills to designate targets within RPV imagery.

Observing motion by multiple visual tracking agents

Abstract: This paper describes a method to observe a moving object with multiple visual tracking agents. When a robot vision watches an object, it employs several tracking agents to monitor key features of the object. Each tracking agent is controlled by its visual feedback. In order to perform robust tracking, the authors introduce constraint control between agents. This method is effective in observing a motion of not only a single solid object but also a structured object such as a human hand. Several examples applied to 3D motion are shown. >