Radar-Based Activity Recognition in Strictly Privacy-Sensitive Settings Through Deep Feature Learning

Human activity recognition in privacy-sensitive environments, such as bathrooms, presents significant challenges due to the need for non-invasive and anonymous monitoring. Traditional vision-based methods raise privacy concerns, while wearable sensors require user compliance. This study explores a r...

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Main Authors: Giovanni Diraco, Gabriele Rescio, Alessandro Leone
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Biomimetics
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Online Access:https://www.mdpi.com/2313-7673/10/4/243
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author Giovanni Diraco
Gabriele Rescio
Alessandro Leone
author_facet Giovanni Diraco
Gabriele Rescio
Alessandro Leone
author_sort Giovanni Diraco
collection DOAJ
description Human activity recognition in privacy-sensitive environments, such as bathrooms, presents significant challenges due to the need for non-invasive and anonymous monitoring. Traditional vision-based methods raise privacy concerns, while wearable sensors require user compliance. This study explores a radar-based approach for recognizing the activities of daily living in a bathroom setting, utilizing a BGT60TR13C Xensiv 60 GHz radar, manufactured by Infineon Technologies AG (Munich, Germany, EU), to classify human movements without capturing identifiable biometric features. A dataset was collected from seven volunteers performing ten activities which are part of daily living, including activities unique to bathroom environments, such as face washing, teeth brushing, dressing/undressing, and resting on the toilet seat. Deep learning models based on pre-trained feature extractors combined with bidirectional long short-term memory networks were employed for classification. Among the 16 pre-trained networks evaluated, DenseNet201 achieved the highest overall accuracy (97.02%), followed by ResNet50 (94.57%), with the classification accuracy varying by activity. The results highlight the feasibility of Doppler radar-based human activity recognition in privacy-sensitive settings, demonstrating strong recognition performance for most activities while identifying lying down and getting up as more challenging cases due to their motion similarity. The findings suggest that radar-based human activity recognition is a viable alternative to other more invasive monitoring systems (e.g., camera-based), offering an effective, privacy-preserving solution for smart home and healthcare applications.
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spelling doaj-art-e0c1b7df10e743eea4386c2e5324ca2b2025-08-20T03:14:14ZengMDPI AGBiomimetics2313-76732025-04-0110424310.3390/biomimetics10040243Radar-Based Activity Recognition in Strictly Privacy-Sensitive Settings Through Deep Feature LearningGiovanni Diraco0Gabriele Rescio1Alessandro Leone2National Research Council of Italy, Institute for Microelectronics and Microsystems, 73100 Lecce, ItalyNational Research Council of Italy, Institute for Microelectronics and Microsystems, 73100 Lecce, ItalyNational Research Council of Italy, Institute for Microelectronics and Microsystems, 73100 Lecce, ItalyHuman activity recognition in privacy-sensitive environments, such as bathrooms, presents significant challenges due to the need for non-invasive and anonymous monitoring. Traditional vision-based methods raise privacy concerns, while wearable sensors require user compliance. This study explores a radar-based approach for recognizing the activities of daily living in a bathroom setting, utilizing a BGT60TR13C Xensiv 60 GHz radar, manufactured by Infineon Technologies AG (Munich, Germany, EU), to classify human movements without capturing identifiable biometric features. A dataset was collected from seven volunteers performing ten activities which are part of daily living, including activities unique to bathroom environments, such as face washing, teeth brushing, dressing/undressing, and resting on the toilet seat. Deep learning models based on pre-trained feature extractors combined with bidirectional long short-term memory networks were employed for classification. Among the 16 pre-trained networks evaluated, DenseNet201 achieved the highest overall accuracy (97.02%), followed by ResNet50 (94.57%), with the classification accuracy varying by activity. The results highlight the feasibility of Doppler radar-based human activity recognition in privacy-sensitive settings, demonstrating strong recognition performance for most activities while identifying lying down and getting up as more challenging cases due to their motion similarity. The findings suggest that radar-based human activity recognition is a viable alternative to other more invasive monitoring systems (e.g., camera-based), offering an effective, privacy-preserving solution for smart home and healthcare applications.https://www.mdpi.com/2313-7673/10/4/243human activity recognitionFMCW radardeep feature learningprivacy
spellingShingle Giovanni Diraco
Gabriele Rescio
Alessandro Leone
Radar-Based Activity Recognition in Strictly Privacy-Sensitive Settings Through Deep Feature Learning
Biomimetics
human activity recognition
FMCW radar
deep feature learning
privacy
title Radar-Based Activity Recognition in Strictly Privacy-Sensitive Settings Through Deep Feature Learning
title_full Radar-Based Activity Recognition in Strictly Privacy-Sensitive Settings Through Deep Feature Learning
title_fullStr Radar-Based Activity Recognition in Strictly Privacy-Sensitive Settings Through Deep Feature Learning
title_full_unstemmed Radar-Based Activity Recognition in Strictly Privacy-Sensitive Settings Through Deep Feature Learning
title_short Radar-Based Activity Recognition in Strictly Privacy-Sensitive Settings Through Deep Feature Learning
title_sort radar based activity recognition in strictly privacy sensitive settings through deep feature learning
topic human activity recognition
FMCW radar
deep feature learning
privacy
url https://www.mdpi.com/2313-7673/10/4/243
work_keys_str_mv AT giovannidiraco radarbasedactivityrecognitioninstrictlyprivacysensitivesettingsthroughdeepfeaturelearning
AT gabrielerescio radarbasedactivityrecognitioninstrictlyprivacysensitivesettingsthroughdeepfeaturelearning
AT alessandroleone radarbasedactivityrecognitioninstrictlyprivacysensitivesettingsthroughdeepfeaturelearning