Guidelines for the Eye Tracker Calibration Using Points of Regard

Kasprowski, Paweł; Harężlak, Katarzyna; Stasch, Mateusz

doi:10.1007/978-3-319-06596-0_21

Cited by 30 publications

(20 citation statements)

References 15 publications

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“…The problem of noise, always present in measured time series [ 35 ], possibly resulting from environmental and measurement errors [ 36 ], as well as introduced by the oculomotor system, was addressed before each time series’ examination. Previous research conducted by means of the same device used in this study revealed the existence of linear components in registered signals [ 37 ]. Thus, for the purpose of noise elimination, registered signals were analysed in the frequency domain.…”

Section: Methodsmentioning

confidence: 89%

Searching for Chaos Evidence in Eye Movement Signals

Harężlak

Kasprowski

2018

Entropy

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Most naturally-occurring physical phenomena are examples of nonlinear dynamic systems, the functioning of which attracts many researchers seeking to unveil their nature. The research presented in this paper is aimed at exploring eye movement dynamic features in terms of the existence of chaotic nature. Nonlinear time series analysis methods were used for this purpose. Two time series features were studied: fractal dimension and entropy, by utilising the embedding theory. The methods were applied to the data collected during the experiment with "jumping point" stimulus. Eye movements were registered by means of the Jazz-novo eye tracker. One thousand three hundred and ninety two (1392) time series were defined, based on the horizontal velocity of eye movements registered during imposed, prolonged fixations. In order to conduct detailed analysis of the signal and identify differences contributing to the observed patterns of behaviour in time scale, fractal dimension and entropy were evaluated in various time series intervals. The influence of the noise contained in the data and the impact of the utilized filter on the obtained results were also studied. The low pass filter was used for the purpose of noise reduction with a 50 Hz cut-off frequency, estimated by means of the Fourier transform and all concerned methods were applied to time series before and after noise reduction. These studies provided some premises, which allow perceiving eye movements as observed chaotic data: characteristic of a space-time separation plot, low and non-integer time series dimension, and the time series entropy characteristic for chaotic systems.

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Section: Methodsmentioning

confidence: 89%

Searching for Chaos Evidence in Eye Movement Signals

Harężlak

Kasprowski

2018

Entropy

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“…To compensate for those nonlinearities that could be subject specific and session specific or that were unknown, we developed an empirical calibration procedure that was self-adapting to the participant’s size and position and to the different setup dimensions ( Harezlak et al 2014 ; Kasprowski et al 2014 ). The goal of the calibration was to establish the transform functions that compensated for spatial distortions by linking the EyeLink eye position signals in volts and the corresponding KINARM-compatible gaze position in centimeters on the screen, on the basis of a target fixation behavior ( Fig.…”

Section: Methodsmentioning

confidence: 99%

Real-time visuomotor behavior and electrophysiology recording setup for use with humans and monkeys

Haan

Brochier

Grün

et al. 2018

Journal of Neurophysiology

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Large-scale network dynamics in multiple visuomotor areas is of great interest in the study of eye-hand coordination in both human and monkey. To explore this, it is essential to develop a setup that allows for precise tracking of eye and hand movements. It is desirable that it is able to generate mechanical or visual perturbations of hand trajectories so that eye-hand coordination can be studied in a variety of conditions. There are simple solutions that satisfy these requirements for hand movements performed in the horizontal plane while visual stimuli and hand feedback are presented in the vertical plane. However, this spatial dissociation requires cognitive rules for eye-hand coordination different from eye-hand movements performed in the same space, as is the case in most natural conditions. Here we present an innovative solution for the precise tracking of eye and hand movements in a single reference frame. Importantly, our solution allows behavioral explorations under normal and perturbed conditions in both humans and monkeys. It is based on the integration of two noninvasive commercially available systems to achieve online control and synchronous recording of eye (EyeLink) and hand (KINARM) positions during interactive visuomotor tasks. We also present an eye calibration method compatible with different eye trackers that compensates for nonlinearities caused by the system's geometry. Our setup monitors the two effectors in real time with high spatial and temporal resolution and simultaneously outputs behavioral and neuronal data to an external data acquisition system using a common data format.NEW & NOTEWORTHY We developed a new setup for studying eye-hand coordination in humans and monkeys that monitors the two effectors in real time in a common reference frame. Our eye calibration method allows us to track gaze positions relative to visual stimuli presented in the horizontal workspace of the hand movements. This method compensates for nonlinearities caused by the system’s geometry and transforms kinematics signals from the eye tracker into the same coordinate system as hand and targets.

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“…It is further used to provide coordinates of user's gazes ( 1 ). Because of idiosyncratic features of the oculomotor system, this process is conducted independently for each examined person [ 13 ].

where x e and y e represent the data obtained from an eye tracker and x s and y s are the estimated gaze coordinates on a screen.…”

Section: Eye Tracking Basicsmentioning

confidence: 99%

Vision Diagnostics and Treatment System for Children with Disabilities

Kasprowski

Harężlak

2018

Journal of Healthcare Engineering

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Vision plays a crucial role in children's mental development. Therefore, early diagnosis of any vision disparities and implementation of a correct therapy is very important. However, carrying out such a procedure in case of young children and especially children with brain dysfunctions poses some limitations due to cooperation problems. The vision diagnostics and treatment (VisDaT) system presented in this paper is meant to help therapists in proper diagnosis and treatment involving such children. It utilizes a computer connected to two monitors and equipped with a specialized software. The main system components are as follows: an eye tracker recording child's eye movements and a digital camera monitoring online child's reactions. The system is equipped with a specialized software, which creates the opportunity to stimulate children's vision with a dedicated stimulus and post hoc analyses of recorded sessions, which enable making decision as to the future treatment.

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Guidelines for the Eye Tracker Calibration Using Points of Regard

Cited by 30 publications

References 15 publications

Searching for Chaos Evidence in Eye Movement Signals

Searching for Chaos Evidence in Eye Movement Signals

Real-time visuomotor behavior and electrophysiology recording setup for use with humans and monkeys

Vision Diagnostics and Treatment System for Children with Disabilities

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