Natural locomotion based on a reduced set of inertial sensors: Decoupling body and head directions indoors.
Inertial sensors offer the potential for integration into wireless virtual reality systems that allow the users to walk freely through virtual environments. However, owing to drift errors, inertial sensors cannot accurately estimate head and body orientations in the long run, and when walking indoor...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2018-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC5886520?pdf=render |
| _version_ | 1819080243277725696 |
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| author | Ernesto de la Rubia Antonio Diaz-Estrella Arcadio Reyes-Lecuona Alyson Langley Michael Brown Sarah Sharples |
| author_facet | Ernesto de la Rubia Antonio Diaz-Estrella Arcadio Reyes-Lecuona Alyson Langley Michael Brown Sarah Sharples |
| author_sort | Ernesto de la Rubia |
| collection | DOAJ |
| description | Inertial sensors offer the potential for integration into wireless virtual reality systems that allow the users to walk freely through virtual environments. However, owing to drift errors, inertial sensors cannot accurately estimate head and body orientations in the long run, and when walking indoors, this error cannot be corrected by magnetometers, due to the magnetic field distortion created by ferromagnetic materials present in buildings. This paper proposes a technique, called EHBD (Equalization of Head and Body Directions), to address this problem using two head- and shoulder-located magnetometers. Due to their proximity, their distortions are assumed to be similar and the magnetometer measurements are used to detect when the user is looking straight forward. Then, the system corrects the discrepancies between the estimated directions of the head and the shoulder, which are provided by gyroscopes and consequently are affected by drift errors. An experiment is conducted to evaluate the performance of this technique in two tasks (navigation and navigation plus exploration) and using two different locomotion techniques: (1) gaze-directed mode (GD) in which the walking direction is forced to be the same as the head direction, and (2) decoupled direction mode (DD) in which the walking direction can be different from the viewing direction. The obtained results show that both locomotion modes show similar matching of the target path during the navigation task, while DD's path matches the target path more closely than GD in the navigation plus exploration task. These results validate the EHBD technique especially when allowing different walking and viewing directions in the navigation plus exploration tasks, as expected. While the proposed method does not reach the accuracy of optical tracking (ideal case), it is an acceptable and satisfactory solution for users and is much more compact, portable and economical. |
| first_indexed | 2024-12-21T19:41:47Z |
| format | Article |
| id | doaj.art-4c9a135625a648aebb358ab627710126 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-21T19:41:47Z |
| publishDate | 2018-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-4c9a135625a648aebb358ab6277101262022-12-21T18:52:26ZengPublic Library of Science (PLoS)PLoS ONE1932-62032018-01-01134e019519110.1371/journal.pone.0195191Natural locomotion based on a reduced set of inertial sensors: Decoupling body and head directions indoors.Ernesto de la RubiaAntonio Diaz-EstrellaArcadio Reyes-LecuonaAlyson LangleyMichael BrownSarah SharplesInertial sensors offer the potential for integration into wireless virtual reality systems that allow the users to walk freely through virtual environments. However, owing to drift errors, inertial sensors cannot accurately estimate head and body orientations in the long run, and when walking indoors, this error cannot be corrected by magnetometers, due to the magnetic field distortion created by ferromagnetic materials present in buildings. This paper proposes a technique, called EHBD (Equalization of Head and Body Directions), to address this problem using two head- and shoulder-located magnetometers. Due to their proximity, their distortions are assumed to be similar and the magnetometer measurements are used to detect when the user is looking straight forward. Then, the system corrects the discrepancies between the estimated directions of the head and the shoulder, which are provided by gyroscopes and consequently are affected by drift errors. An experiment is conducted to evaluate the performance of this technique in two tasks (navigation and navigation plus exploration) and using two different locomotion techniques: (1) gaze-directed mode (GD) in which the walking direction is forced to be the same as the head direction, and (2) decoupled direction mode (DD) in which the walking direction can be different from the viewing direction. The obtained results show that both locomotion modes show similar matching of the target path during the navigation task, while DD's path matches the target path more closely than GD in the navigation plus exploration task. These results validate the EHBD technique especially when allowing different walking and viewing directions in the navigation plus exploration tasks, as expected. While the proposed method does not reach the accuracy of optical tracking (ideal case), it is an acceptable and satisfactory solution for users and is much more compact, portable and economical.http://europepmc.org/articles/PMC5886520?pdf=render |
| spellingShingle | Ernesto de la Rubia Antonio Diaz-Estrella Arcadio Reyes-Lecuona Alyson Langley Michael Brown Sarah Sharples Natural locomotion based on a reduced set of inertial sensors: Decoupling body and head directions indoors. PLoS ONE |
| title | Natural locomotion based on a reduced set of inertial sensors: Decoupling body and head directions indoors. |
| title_full | Natural locomotion based on a reduced set of inertial sensors: Decoupling body and head directions indoors. |
| title_fullStr | Natural locomotion based on a reduced set of inertial sensors: Decoupling body and head directions indoors. |
| title_full_unstemmed | Natural locomotion based on a reduced set of inertial sensors: Decoupling body and head directions indoors. |
| title_short | Natural locomotion based on a reduced set of inertial sensors: Decoupling body and head directions indoors. |
| title_sort | natural locomotion based on a reduced set of inertial sensors decoupling body and head directions indoors |
| url | http://europepmc.org/articles/PMC5886520?pdf=render |
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