Human Activity Recognition in the Presence of Occlusion

The presence of occlusion in human activity recognition (HAR) tasks hinders the performance of recognition algorithms, as it is responsible for the loss of crucial motion data. Although it is intuitive that it may occur in almost any real-life environment, it is often underestimated in most research...

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Main Authors: Ioannis Vernikos, Theodoros Spyropoulos, Evaggelos Spyrou, Phivos Mylonas
Format: Article
Language:English
Published: MDPI AG 2023-05-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/23/10/4899
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author Ioannis Vernikos
Theodoros Spyropoulos
Evaggelos Spyrou
Phivos Mylonas
author_facet Ioannis Vernikos
Theodoros Spyropoulos
Evaggelos Spyrou
Phivos Mylonas
author_sort Ioannis Vernikos
collection DOAJ
description The presence of occlusion in human activity recognition (HAR) tasks hinders the performance of recognition algorithms, as it is responsible for the loss of crucial motion data. Although it is intuitive that it may occur in almost any real-life environment, it is often underestimated in most research works, which tend to rely on datasets that have been collected under ideal conditions, i.e., without any occlusion. In this work, we present an approach that aimed to deal with occlusion in an HAR task. We relied on previous work on HAR and artificially created occluded data samples, assuming that occlusion may prevent the recognition of one or two body parts. The HAR approach we used is based on a Convolutional Neural Network (CNN) that has been trained using 2D representations of 3D skeletal motion. We considered cases in which the network was trained with and without occluded samples and evaluated our approach in single-view, cross-view, and cross-subject cases and using two large scale human motion datasets. Our experimental results indicate that the proposed training strategy is able to provide a significant boost of performance in the presence of occlusion.
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spelling doaj.art-d92e574136a1465eb92e31009be681a32023-11-18T03:14:14ZengMDPI AGSensors1424-82202023-05-012310489910.3390/s23104899Human Activity Recognition in the Presence of OcclusionIoannis Vernikos0Theodoros Spyropoulos1Evaggelos Spyrou2Phivos Mylonas3Department of Informatics and Telecommunications, University of Thessaly, 35131 Lamia, GreeceDepartment of Digital Systems, University of Piraeus, 18534 Piraeus, GreeceDepartment of Informatics and Telecommunications, University of Thessaly, 35131 Lamia, GreeceDepartment of Informatics and Computer Engineering, University of West Attica, Egaleo Park, 12243 Athens, GreeceThe presence of occlusion in human activity recognition (HAR) tasks hinders the performance of recognition algorithms, as it is responsible for the loss of crucial motion data. Although it is intuitive that it may occur in almost any real-life environment, it is often underestimated in most research works, which tend to rely on datasets that have been collected under ideal conditions, i.e., without any occlusion. In this work, we present an approach that aimed to deal with occlusion in an HAR task. We relied on previous work on HAR and artificially created occluded data samples, assuming that occlusion may prevent the recognition of one or two body parts. The HAR approach we used is based on a Convolutional Neural Network (CNN) that has been trained using 2D representations of 3D skeletal motion. We considered cases in which the network was trained with and without occluded samples and evaluated our approach in single-view, cross-view, and cross-subject cases and using two large scale human motion datasets. Our experimental results indicate that the proposed training strategy is able to provide a significant boost of performance in the presence of occlusion.https://www.mdpi.com/1424-8220/23/10/4899human activity recognitionocclusiondeep learningconvolutional neural networks
spellingShingle Ioannis Vernikos
Theodoros Spyropoulos
Evaggelos Spyrou
Phivos Mylonas
Human Activity Recognition in the Presence of Occlusion
Sensors
human activity recognition
occlusion
deep learning
convolutional neural networks
title Human Activity Recognition in the Presence of Occlusion
title_full Human Activity Recognition in the Presence of Occlusion
title_fullStr Human Activity Recognition in the Presence of Occlusion
title_full_unstemmed Human Activity Recognition in the Presence of Occlusion
title_short Human Activity Recognition in the Presence of Occlusion
title_sort human activity recognition in the presence of occlusion
topic human activity recognition
occlusion
deep learning
convolutional neural networks
url https://www.mdpi.com/1424-8220/23/10/4899
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