Validation of Foot Placement Locations from Ankle Data of a Kinect v2 Sensor

The Kinect v2 sensor may be a cheap and easy to use sensor to quantify gait in clinical settings, especially when applied in set-ups integrating multiple Kinect sensors to increase the measurement volume. Reliable estimates of foot placement locations are required to quantify spatial gait parameters...

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Main Authors: Daphne Geerse, Bert Coolen, Detmar Kolijn, Melvyn Roerdink
Format: Article
Language:English
Published: MDPI AG 2017-10-01
Series:Sensors
Subjects:
Online Access:https://www.mdpi.com/1424-8220/17/10/2301
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author Daphne Geerse
Bert Coolen
Detmar Kolijn
Melvyn Roerdink
author_facet Daphne Geerse
Bert Coolen
Detmar Kolijn
Melvyn Roerdink
author_sort Daphne Geerse
collection DOAJ
description The Kinect v2 sensor may be a cheap and easy to use sensor to quantify gait in clinical settings, especially when applied in set-ups integrating multiple Kinect sensors to increase the measurement volume. Reliable estimates of foot placement locations are required to quantify spatial gait parameters. This study aimed to systematically evaluate the effects of distance from the sensor, side and step length on estimates of foot placement locations based on Kinect’s ankle body points. Subjects (n = 12) performed stepping trials at imposed foot placement locations distanced 2 m or 3 m from the Kinect sensor (distance), for left and right foot placement locations (side), and for five imposed step lengths. Body points’ time series of the lower extremities were recorded with a Kinect v2 sensor, placed frontoparallelly on the left side, and a gold-standard motion-registration system. Foot placement locations, step lengths, and stepping accuracies were compared between systems using repeated-measures ANOVAs, agreement statistics and two one-sided t-tests to test equivalence. For the right side at the 2 m distance from the sensor we found significant between-systems differences in foot placement locations and step lengths, and evidence for nonequivalence. This distance by side effect was likely caused by differences in body orientation relative to the Kinect sensor. It can be reduced by using Kinect’s higher-dimensional depth data to estimate foot placement locations directly from the foot’s point cloud and/or by using smaller inter-sensor distances in the case of a multi-Kinect v2 set-up to estimate foot placement locations at greater distances from the sensor.
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spelling doaj.art-cb694c94840b432eab42e683d904e3f52022-12-22T03:09:55ZengMDPI AGSensors1424-82202017-10-011710230110.3390/s17102301s17102301Validation of Foot Placement Locations from Ankle Data of a Kinect v2 SensorDaphne Geerse0Bert Coolen1Detmar Kolijn2Melvyn Roerdink3Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Van der Boechorststraat 7, 1081 BT Amsterdam, The NetherlandsDepartment of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Van der Boechorststraat 7, 1081 BT Amsterdam, The NetherlandsDepartment of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Van der Boechorststraat 7, 1081 BT Amsterdam, The NetherlandsDepartment of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Van der Boechorststraat 7, 1081 BT Amsterdam, The NetherlandsThe Kinect v2 sensor may be a cheap and easy to use sensor to quantify gait in clinical settings, especially when applied in set-ups integrating multiple Kinect sensors to increase the measurement volume. Reliable estimates of foot placement locations are required to quantify spatial gait parameters. This study aimed to systematically evaluate the effects of distance from the sensor, side and step length on estimates of foot placement locations based on Kinect’s ankle body points. Subjects (n = 12) performed stepping trials at imposed foot placement locations distanced 2 m or 3 m from the Kinect sensor (distance), for left and right foot placement locations (side), and for five imposed step lengths. Body points’ time series of the lower extremities were recorded with a Kinect v2 sensor, placed frontoparallelly on the left side, and a gold-standard motion-registration system. Foot placement locations, step lengths, and stepping accuracies were compared between systems using repeated-measures ANOVAs, agreement statistics and two one-sided t-tests to test equivalence. For the right side at the 2 m distance from the sensor we found significant between-systems differences in foot placement locations and step lengths, and evidence for nonequivalence. This distance by side effect was likely caused by differences in body orientation relative to the Kinect sensor. It can be reduced by using Kinect’s higher-dimensional depth data to estimate foot placement locations directly from the foot’s point cloud and/or by using smaller inter-sensor distances in the case of a multi-Kinect v2 set-up to estimate foot placement locations at greater distances from the sensor.https://www.mdpi.com/1424-8220/17/10/2301Kinect v2 sensorfoot placement locationsgaitvalidationorientationTOST procedure
spellingShingle Daphne Geerse
Bert Coolen
Detmar Kolijn
Melvyn Roerdink
Validation of Foot Placement Locations from Ankle Data of a Kinect v2 Sensor
Sensors
Kinect v2 sensor
foot placement locations
gait
validation
orientation
TOST procedure
title Validation of Foot Placement Locations from Ankle Data of a Kinect v2 Sensor
title_full Validation of Foot Placement Locations from Ankle Data of a Kinect v2 Sensor
title_fullStr Validation of Foot Placement Locations from Ankle Data of a Kinect v2 Sensor
title_full_unstemmed Validation of Foot Placement Locations from Ankle Data of a Kinect v2 Sensor
title_short Validation of Foot Placement Locations from Ankle Data of a Kinect v2 Sensor
title_sort validation of foot placement locations from ankle data of a kinect v2 sensor
topic Kinect v2 sensor
foot placement locations
gait
validation
orientation
TOST procedure
url https://www.mdpi.com/1424-8220/17/10/2301
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AT detmarkolijn validationoffootplacementlocationsfromankledataofakinectv2sensor
AT melvynroerdink validationoffootplacementlocationsfromankledataofakinectv2sensor