225 Works

Eye-tracking Deaf and hearing viewing of sign language interpreted news broadcasts

In this study, the viewing habits of deaf and hearing adults are investigated using eye tracking while they watched interpreted news broadcasts. The study shows that deaf viewers primarily focus on the interpreter and secondarily access picture material, but make very little use of subtitles or lip-reading. In contrast, hearing viewers prioritise pictorial content but also spend significant proportions of time examining subtitles, lip-reading and even watching the interpreter. Viewing patterns are dependent on pictorial...

Dummy eye measurements of microsaccades: Testing the influence of system noise and head movements on microsaccade detection in a popular video-based eye tracker

Whereas early studies of microsaccades have predominantly relied on custom-built eye trackers and manual tagging of microsaccades, more recent work tends to use video-based eye tracking and automated algorithms for microsaccade detection. While data from these newer studies suggest that microsaccades can be reliably detected with video-based systems, this has not been systematically evaluated. I here present a method and data examining microsaccade detection in an often used video-based system (the Eyelink II system) and...

Fixation Region Overlap: A quantitative method for the analysis of fixational eye movement patterns

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This article presents a new method for the quantitative analyses of fixation patterns in eye tracking data. The Fixation Region Overlap Analysis (FROA) uses thresholded spatial distributions of fixation frequency or duration to determine regions-of-interest (ROIs). The locations of these ROIs are contrasted with fixation regions of other empirically-derived, or modelled, data patterns by comparing region pixel overlap. A Monte Carlo procedure is used to assess the statistical significance of fixation region overlap based on...

Error Correction in Vergence Eye Movements: Evidence Supporting Hering’s Law

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In pure symmetrical vergence eye movements, a fusion initiating component quickly brings the eyes close to the desired position. A small error usually remains after this response which must be corrected to attain the small final vergence error (i.e., fixation disparity). Error correction will usually involve both version and version movements so possible mechanisms include: small saccades, smooth pursuit, symmetrical vergence, or some combination. Alternatively, an asymmetrical vergence or uniocular slow eye movement could be...

Heterophoria: Vergence stability and visual acuity after asymmetric saccades

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Many patients with heterophoria report on symptoms related to impaired vision. To investigate whether these symptoms are provoked by saccades this study examines whether in heterophoria effects on intrasaccadic and postsaccadic vergence movements are linked to effects on visual performance. Visual acuity was measured in 35 healthy subjects during fixation and immediately after asymmetric diverging saccades. Binocular position traces were recorded by video-oculography. Subjects with exophoria showed larger intrasaccadic divergence amplitudes, which in turn led...

The effect of a temporary absence of target velocity information on visual tracking

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Experiments with the Rashbass ‘step-ramp’ paradigm have revealed that the initial catchup saccade that occurs near pursuit onset uses target velocity as well as position information in its programming. Information about both position and motion also influences smooth pursuit. To investigate the timing of velocity sampling near the initiation of saccades and smooth pursuit, we analyzed the eye movements made in nine ‘step-ramp’ conditions, produced by combining –2, 0 and +2 deg steps with –8,...

“Trait” and “state” aspects of fixation disparity during reading

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In our study, 14 subjects read 60 sentences from the Potsdam Sentence Corpus twice (viewing distance: 60 cm), while eye movements were measured with the EyeLink II. We analyzed fixation disparities for complete sentence replications (N=388). After subtracting the average fixation disparity of each sentence from each observation (which gave the “state” fixation disparity), 99% of all remaining fixation disparities were aligned, i.e. smaller than one character width (20 min arc) – depending mostly on...

Task-relevant spatialized auditory cues enhance attention orientation and peripheral target detection in natural scenes

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Concurrent auditory stimuli have been shown to enhance detection of abstract visual targets in experimental setups with little ecological validity. We presented 11 participants, wearing an eye-tracking device, with a visual detection task in an immersive audiovisual environment replicating a real-world environment. The participants were to fixate on a visual target and to press a key when they were confident of having detected the target. The visual world was accompanied by a task-relevant or task-irrelevant...

Eye-tracking multi-word units: some methodological questions

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Eye-tracking in linguistics has focused mainly on reading at the level of the word or sentence. In this paper we discuss how the phenomenon of formulaic language might best be examined using this methodology. Formulaic language is fundamentally multi-word in nature, therefore an approach to eye-tracking that considers the “word” as the basic unit of analysis may require re-evaluation. We review the existing literature on single word and sentence processing, and also those studies that...

Influences of dwell time and cursor control on the performance in gaze driven typing

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In gaze controlled computer interfaces the dwell time is often used as selection criterion. But this solution comes along with several problems, especially in the temporal domain: Eye movement studies on scene perception could demonstrate that fixations of different durations serve different purposes and should therefore be differentiated. The use of dwell time for selection implies the need to distinguish intentional selections from merely per-ceptual processes, described as the Midas touch problem. Moreover, the feedback...

Abstracts of the 17th European Conference on Eye Movements 2013

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This document contains all abstracts of the 17th European Conference on Eye Movements, August 11-16 2013 in Lund, Sweden ECEM 2013 has been the 17th European Conference on Eye Movements, with the original aims ‘to exchange information on current research, equipment and software’ remaining at the forefront. ECEM is transdisciplinary, promoting new approaches, co-operation between research fields and communication between researchers. It has grown from it’s origins as a small, specialist conference to a large...

Vergence tracking: a tool to assess oculomotor performance in stereoscopic displays

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Oculomotor conflict induced between the accommodative and vergence components in stereoscopic displays represents an unnatural viewing condition. There is now some evidence that stereoscopic viewing may induce discomfort and changes in oculomotor parameters. The present study sought to measure oculomotor performance during stereoscopic viewing. Using a 3D stereo setup and an eye-tracker, vergence responses were measured during 20-min exposure to a virtual visual target oscillating in depth, which participants had to track. The results showed...

Examining the visual screening patterns of emotional facial expressions with gender, age and lateralization

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The main objective of the study is to investigate the effects of age of model, gender of observer, and lateralization on visual screening patterns while looking at the emotional facial expressions. Data were collected through eye tracking methodology. The areas of interests were set to include eyes, nose and mouth. The selected eye metrics were first fixation duration, fixation duration and fixation count. Those eye tracking metrics were recorded for different emotional expressions (sad, happy,...

Comparing graphs and text: Effects of complexity and task

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Graphs are commonly believed to facilitate users’ compre-hension. We explored the effect of graphs on comprehension compared to text, manipulating content complexity (single bar vs. double bar graphs) and question type (point-locating vs. comparison questions). A total 78 college students viewed graph and text stimuli and answered comprehension questions while their eye movements were recorded. The results indicate that students do not always process graphs more efficiently than text conveying the same information. Students processed...

Anticipation of physical causality guides eye movements

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Causality is a unique feature of human perception. We present here a behavioral investigation of the influence of physical causality during visual pursuit of object collisions. Pursuit and saccadic eye movements of human subjects were recorded during ocular pursuit of two concurrently launched targets, one that moved according to the laws of Newtonian mechanics (the causal target) and the other one that moved in a physically implausible direction (the non-causal target). We found that anticipation...

Direction Estimation Model for Gaze Controlled Systems

Pawanesh Abrol &
Detection of gaze requires estimation of the position and the relation between user’s pupil and glint. This position is mapped into the region of interest using different edge detectors by detecting the glint coordinates and further gaze direction. In this research paper, a Gaze Direction Estimation (GDE) model has been proposed for the comparative analysis of two standard edge detectors Canny and Sobel for estimating automatic detection of the glint, its coordinates and subsequently the...

Examining the validity of the total dwell time of eye fixations to identify landmarks in a building

, Alain De Wulf, , Philippe De Maeyer &
It is uncertain to what extent the duration of eye fixations reflects the use of landmarks during navigation. Therefore, a study was conducted in which eye tracking data and route descriptions were collected of 23 participants who were highly familiar with the indoor test environment. Based on the total fixation time on different landmark categories, two measures were calculated, namely the calculated landmark category use and the probable landmark category use. Based on the ratio...

Covert Attention Tracking: Towards Two-Dimensional Real-Time Recordings

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Achieving attention tracking as easily as recording eye movements is still beyond reach. However, by exploiting Steady-State Visual Evoked Potentials (SSVEPs) we could recently record in a satisfactory way the horizontal trajectory of covert visuospatial attention in single trials, both when attending target motion and during mental motion extrapolation. Here we show that, despite the different cortical functional architecture for horizontal and vertical motion processing, the same result is obtained for vertical attention tracking. Thus,...

Examining the validity of the total dwell time of eye fixations to identify landmarks in a building

Alain De Wulf, , , & Philippe De Maeyer
It is uncertain to what extent the duration of eye fixations reflects the use of landmarks during navigation. Therefore, a study was conducted in which eye tracking data and route descriptions were collected of 23 participants who were highly familiar with the indoor test environment. Based on the total fixation time on different landmark categories, two measures were calculated, namely the calculated landmark category use and the probable landmark category use. Based on the ratio...

Performance of a simple remote video-based eye tracker with GPU acceleration

Jean-Pierre Du Plessis &
Eye tracking is a well-established tool that is often utilised in research. There are currently many different types of eye trackers available, but they are either expensive, or provide a relatively low sampling frequency. The eye tracker presented in this paper was developed in an effort to address the lack of low-cost high-speed eye trackers. It utilises the Graphical Processing Unit (GPU) in an attempt to parallelise aspects of the process to localize feature points...

Evidence for a Structural Analysis of Target Selection in Picture Viewing

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Spontaneous fixations onto shapes are driven by a structural analysis. But is such analysis also carried out during free viewing of real-world scenes? Here, we analyze how fixation locations in such scenes are related to their region using the region's symmetric axes as a reference. Each fixation location is compared with respect to its nearest symmetric-axis segment by a latitude and a longitude measure. Analyzing the distributions for the two measures we find that there...

Recurrence Metrics for Assessing Eye Movements in Perceptual Experiments

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In a recent study evaluating the impact of image content on the consistency of eye movements in perceptual experiments (Farnand, 2013) image complexity was inversely related to scanpath consistency. This work involved a qualitative analysis of eye movements along with analysis of the number and duration of fixations. No quantitative analysis of scan path consistency was performed. Recently, Anderson et al. developed a quantitative tool - Recurrence Quantification Analysis - for analyzing eye movement patterns...

Idiosyncratic Feature-Based Gaze Mapping

It is argued that polynomial expressions that are normally used for remote, video-based, low cost eye tracking systems, are not always ideal to accommodate individual differences in eye cleft, position of the eye in the socket, corneal bulge, astigmatism, etc. A procedure to identify a set of polynomial expressions that will provide the best possible accuracy for a specific individual is proposed. It is also proposed that regression coefficients are recalculated in real-time, based on...

Do you look where I look? Attention shifts and response preparation following dynamic social cues

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Studies investigating the effects of observing a gaze shift in another person often apply static images of a person with an averted gaze, while measuring response times to a peripheral target. Static images, however, are unlike how we normally perceive gaze shifts of others. Moreover, response times might only reveal the effects of a cue on covert attention and might fail to uncover cueing effects on overt attention or response preparation. We therefore extended the...

High working memory performers have efficient eye movement control systems under Reading Span Test

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Controlled eye movements are critical in performing highly goal oriented behavior such as text reading. Previous studies have examined the relationship between working memory capacity and eye movement control during working memory task. However, the results were inconsistent, due to a methodological issue including the predictability of target location. In the present study, we used Japanese version of reading span test, where the position of to-be-remembered word is not predictable so that more efficient attentional...

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