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MEMS mirror based eye tracking: simulation of the system parameter effect on the accuracy of pupil position estimation

Pomianek Mateusz, Piszczek Marek, Maciejewski Marcin

Metrology and Measurement Systems

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2021

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Vol. 28, nr 4

711--724

EN

Eye tracking systems are mostly video-based methods which require significant computation to achieve good accuracy. An alternative method with comparable accuracy but less computational expense is 2D microelectromechanical (MEMS) mirror scanning. However, this technology is relatively new and there are not many publications on it. The purpose of this study was to examine how individual parameters of system components can affect the accuracy of pupil position estimation. The study was conducted based on a virtual simulator. It was shown that the optimal detector field of view (FOV) depends on the frequency ratio of the MEMS mirror axis. For a value of 1:13, the smallest errors were at 0.1°, 1.65°, 2.3°, and 2.95°. The error for the impact of the signal sampling rate above 3 kHz stabilizes at 0.065° and no longer changes its value regardless of increasing the number of samples. The error for the frequency ratio of the MEMS mirror axis increases linearly in the range of 0.065°-0.1°up to the ratio of 1:230. Above this there is a sudden increase to the average value of 0.3°. The conducted research provides guidance in the selection of parameters for the construction of eye tracking MEMS mirror-based systems.

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Altered postural stability in elderly women following a single session of head-mounted display virtual reality

Cieślik Błażej, Serweta Anna, Federico Sara, Szczepańska-Gieracha Joanna

Acta of Bioengineering and Biomechanics

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2021

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Vol. 23, no. 1

107--111

EN

Purpouse: The aim of this study was to evaluate the effect of a single session of head-mounted display virtual reality on postural stability in elderly women. Methods: Forty-seven female subjects underwent a 20-minute virtual reality session. The mean age of the subjects was 70.12 years. As an immersive source, we used a relaxing virtual reality game with a head-mounted display device. The postural stability test was conducted using a Nintendo Wii force plate. Participants completed a set of three 30-s trials in which they took a quiet bipedal eyes-open stance while standing on a hard surface: before the virtual reality session, immediately after the virtual reality session, and 2 minutes after the virtual reality session. Centre of pressure parameters were analysed in the sagittal and frontal planes. Results: Analysing the results obtained immediately after the virtual reality session, significant differences were observed in almost all examined parameters. In the sagittal plane, centre of pressure path velocity increased by 10% (p < 0.01) and path standard deviation by 15% (p < 0.05). In the frontal plane, centre of pressure path velocity increased by 14% (p < 0.01). After 2 minutes, all examined parameters showed no significant difference compared to before the virtual reality session. Conclusions: Immediately after the virtual reality session, there was an increase in almost all examined parameters. However, after 2 minutes, all examined parameters had returned to baseline. Therefore, to reduce fall risk after a virtual reality session, it is recommended that the subject spend at least 2 minutes in a sitting position.

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Systemy i zastosowania rzeczywistości rozszerzonej

Skórska H. K.

Przegląd Mechaniczny

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2017

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nr 7-8

46--50

PL

W artykule opisano systemy rzeczywistości rozszerzonej (AR) oraz ich zastosowania. Przedstawiono zasadę działania systemów opartych na wykorzystaniu markerów oraz systemów śledzących, jak i sposób wizualizacji, który wpływa na ich klasyfikację. Omówiono wyświetlacze – mobilne typu HMD (okulary, hełmy), projektorowe, przezierne, ekrany. Artykuł obejmuje zagadnienie wybranych zastosowań systemów rzeczywistości rozszerzonej (m.in. dla wojska, motoryzacji, przemysłu, turystyki, architektury, rozrywki itd.).

EN

The article discusses augmented reality systems (AR) and their applications. The principle of operation of marker-based AR systems and systems using tracking devices are presented. Different kinds of displays were discussed: head-mounted displays (glasses, helmets), projection and see through displays as well as screens. The issue of visualization methods and their influence on the classification of AR systems is presented. The article covers the issue of selected applications of augmented reality systems (for military, automotive industry, industry, tourism, architecture, entertainment etc.).