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Human Activities and Postures Recognition: From Inertial Measurements to Quaternion-Based Approaches

This paper presents two approaches to assess the effect of the number of inertial sensors and their location placements on recognition of human postures and activities. Inertial and Magnetic Measurement Units (IMMUs)—which consist of a triad of three-axis accelerometer, three-axis gyroscope, and thr...

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Autores principales: Zmitri, Makia, Fourati, Hassen, Vuillerme, Nicolas
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6806241/
https://www.ncbi.nlm.nih.gov/pubmed/31547055
http://dx.doi.org/10.3390/s19194058
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author Zmitri, Makia
Fourati, Hassen
Vuillerme, Nicolas
author_facet Zmitri, Makia
Fourati, Hassen
Vuillerme, Nicolas
author_sort Zmitri, Makia
collection PubMed
description This paper presents two approaches to assess the effect of the number of inertial sensors and their location placements on recognition of human postures and activities. Inertial and Magnetic Measurement Units (IMMUs)—which consist of a triad of three-axis accelerometer, three-axis gyroscope, and three-axis magnetometer sensors—are used in this work. Five IMMUs are initially used and attached to different body segments. Placements of up to three IMMUs are then considered: back, left foot, and left thigh. The subspace k-nearest neighbors (KNN) classifier is used to achieve the supervised learning process and the recognition task. In a first approach, we feed raw data from three-axis accelerometer and three-axis gyroscope into the classifier without any filtering or pre-processing, unlike what is usually reported in the state-of-the-art where statistical features were computed instead. Results show the efficiency of this method for the recognition of the studied activities and postures. With the proposed algorithm, more than 80% of the activities and postures are correctly classified using one IMMU, placed on the lower back, left thigh, or left foot location, and more than 90% when combining all three placements. In a second approach, we extract attitude, in term of quaternion, from IMMUs in order to more precisely achieve the recognition process. The obtained accuracy results are compared to those obtained when only raw data is exploited. Results show that the use of attitude significantly improves the performance of the classifier, especially for certain specific activities. In that case, it was further shown that using a smaller number of features, with quaternion, in the recognition process leads to a lower computation time and better accuracy.
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spelling pubmed-68062412019-11-07 Human Activities and Postures Recognition: From Inertial Measurements to Quaternion-Based Approaches Zmitri, Makia Fourati, Hassen Vuillerme, Nicolas Sensors (Basel) Article This paper presents two approaches to assess the effect of the number of inertial sensors and their location placements on recognition of human postures and activities. Inertial and Magnetic Measurement Units (IMMUs)—which consist of a triad of three-axis accelerometer, three-axis gyroscope, and three-axis magnetometer sensors—are used in this work. Five IMMUs are initially used and attached to different body segments. Placements of up to three IMMUs are then considered: back, left foot, and left thigh. The subspace k-nearest neighbors (KNN) classifier is used to achieve the supervised learning process and the recognition task. In a first approach, we feed raw data from three-axis accelerometer and three-axis gyroscope into the classifier without any filtering or pre-processing, unlike what is usually reported in the state-of-the-art where statistical features were computed instead. Results show the efficiency of this method for the recognition of the studied activities and postures. With the proposed algorithm, more than 80% of the activities and postures are correctly classified using one IMMU, placed on the lower back, left thigh, or left foot location, and more than 90% when combining all three placements. In a second approach, we extract attitude, in term of quaternion, from IMMUs in order to more precisely achieve the recognition process. The obtained accuracy results are compared to those obtained when only raw data is exploited. Results show that the use of attitude significantly improves the performance of the classifier, especially for certain specific activities. In that case, it was further shown that using a smaller number of features, with quaternion, in the recognition process leads to a lower computation time and better accuracy. MDPI 2019-09-20 /pmc/articles/PMC6806241/ /pubmed/31547055 http://dx.doi.org/10.3390/s19194058 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Zmitri, Makia
Fourati, Hassen
Vuillerme, Nicolas
Human Activities and Postures Recognition: From Inertial Measurements to Quaternion-Based Approaches
title Human Activities and Postures Recognition: From Inertial Measurements to Quaternion-Based Approaches
title_full Human Activities and Postures Recognition: From Inertial Measurements to Quaternion-Based Approaches
title_fullStr Human Activities and Postures Recognition: From Inertial Measurements to Quaternion-Based Approaches
title_full_unstemmed Human Activities and Postures Recognition: From Inertial Measurements to Quaternion-Based Approaches
title_short Human Activities and Postures Recognition: From Inertial Measurements to Quaternion-Based Approaches
title_sort human activities and postures recognition: from inertial measurements to quaternion-based approaches
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6806241/
https://www.ncbi.nlm.nih.gov/pubmed/31547055
http://dx.doi.org/10.3390/s19194058
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