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Total results: 534

PERCLOS as an indicator of slow-onset hypoxia in aviation

Year: 2018

Authors: JE Thropp, JFV Scallon, P Buza

BACKGROUND: PERCLOS is a metric that has been primarily studied in the domain of driver fatigue to predict performance decrements, but there is comparatively less research applying it to aviation, where hypoxia is a safety concern. Hypoxic exposure was expected to increase blink activity, possibly by means of impairing blink inhibition behavior, thereby leading to increased eyelid closure time. METHODS: PERCLOS, blink rate, and blink duration were measured using head-mounted eye-tracking on pilots using a flight simulator inside a hypobaric chamber. Pilot subjects were tasked with programming the autopilot of a G-1000 console according to instructions from a simulated air traffic controller. Data was collected at 5% decrements in blood oxygen saturation (S p o 2) through progressive decreases in hypobaric pressure to model slow-onset hypoxia. RESULTS: PERCLOS, blink rate, and blink duration increased significantly and linearly as a function of decreasing S p o 2, and largely recovered in the posthypoxia normoxia condition. The greatest change in PERCLOS relative to the prehypoxia baseline occurred in the 80% S p o 2 condition, whereas the greatest change in blink rate and duration occurred at 75% S p o 2. As S p o 2 decreased, a higher frequency of long blink durations was observed. DISCUSSION: The increase in blink rate and duration in the absence of task demand manipulation could suggest hypoxia-induced sympathetic excitation and impairment of adaptive blink inhibition behavior. The effect of hypoxia on oculomotor features is also likely task-specific. In consideration of the extensive demand made upon the visual modality in flight, increased PERCLOS may further tax visual information processing.

Eye Tracking Glasses
Simulator

6 versions available

Pre-movement and during-movement visual search behaviours vary depending on expertise and anxiety levels in ten-pin bowling

Year: 2018

Authors: WX Goh, BHY Lim, MJ Wylde

This study investigated the pre-movement and during-movement visual search behaviour (VSB) and quiet eye (QE) of 11 elite versus 10 sub-elite ten-pin bowlers, performing under high-anxiety and low-anxiety conditions. Pre-movement and independent of expertise, bowlers had more fixations and directed them to more locations when performing under high-anxiety compared with low-anxiety. Elite bowlers fixated at more locations closer to the pins in pre-movement than during-movement, with pre-movement QE occurring mostly at the breakpoint and middle arrows. During movement however, bowlers fixated closer to the foul-line at the middle and right dots and arrows, with during-movement-QE occurring at the middle dots and right arrows. Elite bowlers recorded longer QE durations during-movement rather than pre-movement, albeit a later onset during the longish five-step approach prior to ball release compared with sub-elite bowlers. Our results suggest that QE during-movement instead of pre-movement could be more pertinent in differentiating expertise during sporting tasks with a long movement phase and far-aiming target. The relevance of pre-movement or movement-QE in characterising expertise and performance could therefore be sport-dependent. This should be considered when investigating skilled action and developing training programs for skill acquisition.

Eye Tracking Glasses
Software

4 versions available

Predicting and Facilitating the Emergence of Optimal Solutions for a Cooperative “Herding” Task and Testing their Similitude to Contexts Utilizing Full-Body Motion

Year: 2018

Authors: P Nalepka

This study aims to predict and facilitate the emergence of optimal solutions for a cooperative 'herding' task. The utility of such solutions is then tested against contexts requiring full-body motion. The investigation encompasses various methodologies, analyzing the dynamics of cooperative tasks and their resulting effectiveness. By examining these parameters, the study seeks to contribute to the understanding of motion coordination and cooperative behavior, potentially informing fields that require complex motion planning and execution.

Eye Tracking Glasses
Software

4 versions available

Preliminary investigation of sleep-related driving fatigue experiment in Indonesia

Year: 2018

Authors: KH Sanjaya, YMK Sya'Bana, S Hutchinson

Sleep-related driving fatigue has been recognized as one of the main causes of traffic accidents. In Indonesia, experiment-based driving fatigue study is still very limited. Therefore it is necessary to develop a laboratory-based experimental procedure for sleep-related fatigue study. In this preliminary study, we performed a literature review to find references for the procedure and three pilot experiments to test the instruments and procedure to be used in measuring driving fatigue. Three subjects participated, both from experienced and inexperienced drivers. Our pilot experiments were performed on a driving simulator using OpenDS software with brake and lane change test reaction time measurement. We measured sleepiness by using Karolinska Sleepiness Scale (KSS) Questionnaire. The conditions of the experiment were based on illumination intensity as well as pre- and post-lunch session. We found that lane change reaction time is more potential than brake reaction time to measure driving performance as shown by more fluctuating data. Post-lunch seems to induce drowsiness greater than illumination intensity. KSS questionnaire seems non-linear with driving performance data. We need to test further these speculations in the future studies involving a sufficient number of subjects. We also need to compare the effect of circadian rhythm and sleep deprivation on driving fatigue. The use of eye closure and physiological measurement in further study will enable us to measure driving fatigue more objectively. Considering the limitations, more preliminary experiments are required to be performed before conducting the main experiment of driving fatigue.

Simulator
Software

6 versions available

PuRe: Robust pupil detection for real-time pervasive eye tracking

Year: 2018

Authors: T Santini,W Fuhl,E Kasneci

Real-time, accurate, and robust pupil detection is an essential prerequisite to enable pervasive eye-tracking and its applications – e.g., gaze-based human computer interaction, health monitoring, foveated rendering, and advanced driver assistance. However, automated pupil detection has proved to be an intricate task in real-world scenarios due to a large mixture of challenges such as quickly changing illumination and occlusions. In this paper, we introduce the Pupil Reconstructor (PuRe), a method for pupil detection in pervasive scenarios based on a novel edge segment selection and conditional segment combination schemes; the method also includes a confidence measure for the detected pupil. The proposed method was evaluated on over 316,000 images acquired with four distinct head-mounted eye tracking devices. Results show a pupil detection rate improvement of over 10 percentage points w.r.t. state-of-the-art algorithms in the two most challenging data sets (6.46 for all data sets), further pushing the envelope for pupil detection. Moreover, we advance the evaluation protocol of pupil detection algorithms by also considering eye images in which pupils are not present and contributing a new data set of mostly closed eyes images. In this aspect, PuRe improved precision and specificity w.r.t. state-of-the-art algorithms by 25.05 and 10.94 percentage points, respectively, demonstrating the meaningfulness of PuRe’s confidence measure. PuRe operates in real-time for modern eye trackers (at 120 fps) and is fully integrated into EyeRecToo – an open-source state-of-the-art software for pervasive head-mounted eye tracking.

Eye Tracking Glasses
Software

9 versions available

Real-time multiple audio beamforming system

Year: 2018

Authors: J Lindqvist, M Sollenberg

The Cocktail party problem is a known problem within audiology and relates to a person’s ability to understand and separate speech from a noisy background with multiple speakers. This master’s thesis, in collaboration with Eriksholm Research Center, part of the company Oticon, developed a real-time system to help people with Hearing Impairment (HI) handle this problem by using a microphone array and a Minimum Variance Distortionless Response (MVDR) beamformer. The resulting beams yield an Articulation Index Weighted Directivity Index (AI-DI) of above 15 dB. Instead of using a single beam and removing all ambient sources, the system will let the user keep their situational awareness by using Head-Related Transfer Functions (HRTFs) and directing beams at multiple sources and merging the result with an emphasis on the desired source. With the implemented eye-steering technique, the user has the ability to choose a desired source by looking at it. Based on Short-time Objective Intelligibility (STOI) measurements, the system more than doubles the estimated speech intelligibility in situations like the Cocktail party problem. Proposed techniques for implementations of Sound Source Localization (SSL) and Simultaneous Localization and Mapping (SLAM) are included in the report, which would let the system track sources in real-time.

Eye Tracking Glasses
Software

2 versions available

Route previewing results in altered gaze behaviour, increased self-confidence and improved stepping safety in both young and older adults during adaptive …

Year: 2018

Authors: BT Curzon

Older adults with falls risk tend to look away prematurely from targets for safe foot placement to view future hazards; behaviour associated with increased anxiety and stepping inaccuracies. We aimed to determine the effectiveness of route previewing in reducing anxiety and optimizing gaze behaviour and stepping performance of younger and older adults. Nine younger and nine older adults completed six walks with three task complexities over two sessions. Each trial used either an isolated stepping target, or a target followed by either one or two obstacles. Participants with eyes closed, on hearing a signal, opened their eyes and initiated walking (go trials) or stood previewing the route for 10 s before starting (preview trials). Kinematic data were collected using a Vicon motion analysis system. Gaze behaviour was recorded using a Dikablis eye tracker. On average, both older and younger adults fixated the target for significantly longer during walking when they had previewed the route than when they had not. Self-confidence scores were also significantly higher following ‘preview trials’ than ‘go trials’. Stepping performance significantly improved following route previewing (reduced Medial lateral foot placement variability for both groups and reduced anterior/posterior foot placement error in older adults only). These findings implicate route previewing as a potential intervention to increase self-confidence and reduce the risk of tripping in older adults.

Eye Tracking Glasses
Software

14 versions available

Rummage search by expert dyads, novice dyads and novice individuals for objects hidden in houses

Year: 2018

Authors: CA Riggs, HJ Godwin, CM Mann, SJ Smith

Rummage search is the visual and haptic search of complex environments for targets. In this study, rummage search was explored using a novel analytic framework with expert dyads and novice dyads, as well as novice individuals. Participants sought an unknown number of targets placed in four rooms of a residential house. Some targets were plainly visible whereas others were hidden and could only be found through haptic examination. Expert dyads were very good at the task, conducting a slowed, double-checking exhaustive search, while novices both failed to fixate potential target locations and failed to carry out the appropriate action required to search those locations exhaustively. The novice dyads examined more than the novice individuals, but became more superficial in their search. We conclude that effective rummage searching is a skill enhanced by training.

Eye Tracking Glasses
Simulator
Software

6 versions available

Saccade frequency response to visual cues during gait in Parkinson’s disease: the selective role of attention

Year: 2018

Authors: S Stuart, S Lord,B Galna

Gait impairment is a core feature of Parkinson's disease (PD) with implications for falls risk. Visual cues improve gait in PD, but the underlying mechanisms are unclear. Evidence suggests that attention and vision play an important role; however, the relative contribution from each is unclear. Measurement of visual exploration (specifically saccade frequency) during gait allows for real-time measurement of attention and vision. Understanding how visual cues influence visual exploration may allow inferences of the underlying mechanisms to response which could help to develop effective therapeutics. This study aimed to examine saccade frequency during gait in response to a visual cue in PD and older adults and investigate the roles of attention and vision in visual cue response in PD. A mobile eye-tracker measured saccade frequency during gait in 55 people with PD and 32 age-matched controls. Participants walked in a straight line with and without a visual cue (50 cm transverse lines) presented under single task and dual-task (concurrent digit span recall). Saccade frequency was reduced when walking in PD compared to controls; however, visual cues ameliorated saccadic deficit. Visual cues significantly increased saccade frequency in both PD and controls under both single task and dual-task. Attention rather than visual function was central to saccade frequency and gait response to visual cues in PD. In conclusion, this study highlights the impact of visual cues on visual exploration when walking and the important role of attention in PD. Understanding these complex features will help inform intervention development.

Eye Tracking Glasses
Software

12 versions available

Spatial disorientation influences on pilots’ visual scanning and flight performance

Year: 2018

Authors: WD Ledegang,EL Groen

BACKGROUND: Adequate instrument scanning is considered an important countermeasure against spatial disorientation (SD). Remarkably, literature on the relation between SD and pilots’ visual scanning is scarce. The objective of this simulator study was to investigate theinfluence of SD on pilots’ visual scanning and flight performance. METHODS: In a ground-based SD simulator, 10 novice military pilots were asked to manually fly 3 circuits. Unknowingly to the pilots, the final circuit contained one visual and four vestibular SD events. Simulatormotion, flight performance, pilots’ gaze direction, and control inputs were recorded and analyzed. Afterwards the pilots filled in a questionnaire about their recognition of events. RESULTS: Three of the five SD events significantly affected pilots’ flight performanceand gaze behavior. First, the false horizon during the cloud leans induced an unintended roll rate, 0.41 ± 0.36° · s −1 , when the pilots were looking out the window. Second, the Coriolis illusion caused a 0.44 ± 0.18 s delay in the first glance to theattitude indicator and triggered an unintended roll rate, 1.25 ± 1.33° · s −1 , and bank angle deviation of 3.4 ± 3.7° during the coordinated turn. Third, the somatogravic illusion affected pilots’ pitch inputs on the stick, but this seemsto be confounded by inaccurate simulation of the illusion. DISCUSSION: This study provides direct experimental evidence that SD can evoke inappropriate control inputs and can influence the pilots’ scanning behavior, even when SD is not recognized. We conclude that gaze trackingprovides useful feedback on the pilot’s instrument scan during SD simulator training when using appropriate scenarios and simulator motion.

Simulator
Software

7 versions available