Reducing the Impact of Sensor Orientation Variability in Human Activity Recognition Using a Consistent Reference System

Sensor- orientation is a critical aspect in a Human Activity Recognition (HAR) system based on tri-axial signals (such as accelerations); different sensors orientations introduce important errors in the activity recognition process. This paper proposes a new preprocessing module to reduce the negati...

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Main Authors: Manuel Gil-Martín, Javier López-Iniesta, Fernando Fernández-Martínez, Rubén San-Segundo
Format: Article
Language:English
Published: MDPI AG 2023-06-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/23/13/5845
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author Manuel Gil-Martín
Javier López-Iniesta
Fernando Fernández-Martínez
Rubén San-Segundo
author_facet Manuel Gil-Martín
Javier López-Iniesta
Fernando Fernández-Martínez
Rubén San-Segundo
author_sort Manuel Gil-Martín
collection DOAJ
description Sensor- orientation is a critical aspect in a Human Activity Recognition (HAR) system based on tri-axial signals (such as accelerations); different sensors orientations introduce important errors in the activity recognition process. This paper proposes a new preprocessing module to reduce the negative impact of sensor-orientation variability in HAR. Firstly, this module estimates a consistent reference system; then, the tri-axial signals recorded from sensors with different orientations are transformed into this consistent reference system. This new preprocessing has been evaluated to mitigate the effect of different sensor orientations on the classification accuracy in several state-of-the-art HAR systems. The experiments were carried out using a subject-wise cross-validation methodology over six different datasets, including movements and postures. This new preprocessing module provided robust HAR performance even when sudden sensor orientation changes were included during data collection in the six different datasets. As an example, for the WISDM dataset, sensors with different orientations provoked a significant reduction in the classification accuracy of the state-of-the-art system (from 91.57 ± 0.23% to 89.19 ± 0.26%). This important reduction was recovered with the proposed algorithm, increasing the accuracy to 91.46 ± 0.30%, i.e., the same result obtained when all sensors had the same orientation.
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spelling doaj.art-ac54ed24ea9d427fa1b431716672efee2023-11-18T17:27:37ZengMDPI AGSensors1424-82202023-06-012313584510.3390/s23135845Reducing the Impact of Sensor Orientation Variability in Human Activity Recognition Using a Consistent Reference SystemManuel Gil-Martín0Javier López-Iniesta1Fernando Fernández-Martínez2Rubén San-Segundo3Speech Technology and Machine Learning, Information Processing and Telecommunications Center, E.T.S.I. de Telecomunicación, Universidad Politécnica de Madrid, 28040 Madrid, SpainSpeech Technology and Machine Learning, Information Processing and Telecommunications Center, E.T.S.I. de Telecomunicación, Universidad Politécnica de Madrid, 28040 Madrid, SpainSpeech Technology and Machine Learning, Information Processing and Telecommunications Center, E.T.S.I. de Telecomunicación, Universidad Politécnica de Madrid, 28040 Madrid, SpainSpeech Technology and Machine Learning, Information Processing and Telecommunications Center, E.T.S.I. de Telecomunicación, Universidad Politécnica de Madrid, 28040 Madrid, SpainSensor- orientation is a critical aspect in a Human Activity Recognition (HAR) system based on tri-axial signals (such as accelerations); different sensors orientations introduce important errors in the activity recognition process. This paper proposes a new preprocessing module to reduce the negative impact of sensor-orientation variability in HAR. Firstly, this module estimates a consistent reference system; then, the tri-axial signals recorded from sensors with different orientations are transformed into this consistent reference system. This new preprocessing has been evaluated to mitigate the effect of different sensor orientations on the classification accuracy in several state-of-the-art HAR systems. The experiments were carried out using a subject-wise cross-validation methodology over six different datasets, including movements and postures. This new preprocessing module provided robust HAR performance even when sudden sensor orientation changes were included during data collection in the six different datasets. As an example, for the WISDM dataset, sensors with different orientations provoked a significant reduction in the classification accuracy of the state-of-the-art system (from 91.57 ± 0.23% to 89.19 ± 0.26%). This important reduction was recovered with the proposed algorithm, increasing the accuracy to 91.46 ± 0.30%, i.e., the same result obtained when all sensors had the same orientation.https://www.mdpi.com/1424-8220/23/13/5845human activity recognitiongravity estimationsensor-orientation-independentforward movement directionwearable sensorsacceleration signals
spellingShingle Manuel Gil-Martín
Javier López-Iniesta
Fernando Fernández-Martínez
Rubén San-Segundo
Reducing the Impact of Sensor Orientation Variability in Human Activity Recognition Using a Consistent Reference System
Sensors
human activity recognition
gravity estimation
sensor-orientation-independent
forward movement direction
wearable sensors
acceleration signals
title Reducing the Impact of Sensor Orientation Variability in Human Activity Recognition Using a Consistent Reference System
title_full Reducing the Impact of Sensor Orientation Variability in Human Activity Recognition Using a Consistent Reference System
title_fullStr Reducing the Impact of Sensor Orientation Variability in Human Activity Recognition Using a Consistent Reference System
title_full_unstemmed Reducing the Impact of Sensor Orientation Variability in Human Activity Recognition Using a Consistent Reference System
title_short Reducing the Impact of Sensor Orientation Variability in Human Activity Recognition Using a Consistent Reference System
title_sort reducing the impact of sensor orientation variability in human activity recognition using a consistent reference system
topic human activity recognition
gravity estimation
sensor-orientation-independent
forward movement direction
wearable sensors
acceleration signals
url https://www.mdpi.com/1424-8220/23/13/5845
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