Characterizing the Impact of Sampling Rate and Filter Design on the Morphology of Lower Limb Angular Velocities

Eric K. Allseits, Vibhor R Agrawal, Abhishek Prasad, Christopher Bennett, Kyoung Jae Kim

Research output: Contribution to journalArticle

Abstract

The angular velocity of lower limb segments during walking is useful for calculating temporal-spatial parameters and joint kinematics in the inertial measurement unit (IMU)-based gait analysis. While many IMU-based methods for gait analysis have been proposed, configurations of data acquisition and signal conditioning parameter have not been standardized across studies. This study examined the effect of sampling rate and filter design on the characteristic angular velocity waveform obtained from IMUs donned on the lower limbs. Specifically, the frequency analysis of this waveform was performed, and the difference in timing and magnitude of the signal at gait events was evaluated relative to the initial signal. A minimum sampling rate of 35 Hz and a lowpass filter (LPF) cutoff of greater than 10 Hz were found to be appropriate parameters for acquisition and conditioning of the lower limb angular velocity signals. The required low minimum sampling rate suggests that gyroscope data are appropriate for use in bandwidth and battery life limited mobile health applications. Our results also showed that while the commonly employed LPF cutoffs of 5 Hz or less may be appropriate for mid-stance detection, they were not optimal for calculation of heel-strike, toe-off, mid-swing, or angular displacement, obtained with heel-strike and toe-off as delimiters.

Original languageEnglish (US)
Article number8642884
Pages (from-to)4115-4122
Number of pages8
JournalIEEE Sensors Journal
Volume19
Issue number11
DOIs
StatePublished - Jun 1 2019

Fingerprint

Angular velocity
angular velocity
gait
limbs
Gait analysis
Units of measurement
sampling
Sampling
filters
conditioning
waveforms
cut-off
Gyroscopes
walking
Data acquisition
gyroscopes
Signal processing
Kinematics
health
data acquisition

Keywords

  • angular velocity
  • digital filter
  • gyroscope
  • Inertial measurement unit
  • mobile health
  • sampling rate

ASJC Scopus subject areas

  • Instrumentation
  • Electrical and Electronic Engineering

Cite this

Characterizing the Impact of Sampling Rate and Filter Design on the Morphology of Lower Limb Angular Velocities. / Allseits, Eric K.; Agrawal, Vibhor R; Prasad, Abhishek; Bennett, Christopher; Kim, Kyoung Jae.

In: IEEE Sensors Journal, Vol. 19, No. 11, 8642884, 01.06.2019, p. 4115-4122.

Research output: Contribution to journalArticle

@article{64a2699b1d204f4596682058101e8f57,
title = "Characterizing the Impact of Sampling Rate and Filter Design on the Morphology of Lower Limb Angular Velocities",
abstract = "The angular velocity of lower limb segments during walking is useful for calculating temporal-spatial parameters and joint kinematics in the inertial measurement unit (IMU)-based gait analysis. While many IMU-based methods for gait analysis have been proposed, configurations of data acquisition and signal conditioning parameter have not been standardized across studies. This study examined the effect of sampling rate and filter design on the characteristic angular velocity waveform obtained from IMUs donned on the lower limbs. Specifically, the frequency analysis of this waveform was performed, and the difference in timing and magnitude of the signal at gait events was evaluated relative to the initial signal. A minimum sampling rate of 35 Hz and a lowpass filter (LPF) cutoff of greater than 10 Hz were found to be appropriate parameters for acquisition and conditioning of the lower limb angular velocity signals. The required low minimum sampling rate suggests that gyroscope data are appropriate for use in bandwidth and battery life limited mobile health applications. Our results also showed that while the commonly employed LPF cutoffs of 5 Hz or less may be appropriate for mid-stance detection, they were not optimal for calculation of heel-strike, toe-off, mid-swing, or angular displacement, obtained with heel-strike and toe-off as delimiters.",
keywords = "angular velocity, digital filter, gyroscope, Inertial measurement unit, mobile health, sampling rate",
author = "Allseits, {Eric K.} and Agrawal, {Vibhor R} and Abhishek Prasad and Christopher Bennett and Kim, {Kyoung Jae}",
year = "2019",
month = "6",
day = "1",
doi = "10.1109/JSEN.2019.2899724",
language = "English (US)",
volume = "19",
pages = "4115--4122",
journal = "IEEE Sensors Journal",
issn = "1530-437X",
publisher = "Institute of Electrical and Electronics Engineers Inc.",
number = "11",

}

TY - JOUR

T1 - Characterizing the Impact of Sampling Rate and Filter Design on the Morphology of Lower Limb Angular Velocities

AU - Allseits, Eric K.

AU - Agrawal, Vibhor R

AU - Prasad, Abhishek

AU - Bennett, Christopher

AU - Kim, Kyoung Jae

PY - 2019/6/1

Y1 - 2019/6/1

N2 - The angular velocity of lower limb segments during walking is useful for calculating temporal-spatial parameters and joint kinematics in the inertial measurement unit (IMU)-based gait analysis. While many IMU-based methods for gait analysis have been proposed, configurations of data acquisition and signal conditioning parameter have not been standardized across studies. This study examined the effect of sampling rate and filter design on the characteristic angular velocity waveform obtained from IMUs donned on the lower limbs. Specifically, the frequency analysis of this waveform was performed, and the difference in timing and magnitude of the signal at gait events was evaluated relative to the initial signal. A minimum sampling rate of 35 Hz and a lowpass filter (LPF) cutoff of greater than 10 Hz were found to be appropriate parameters for acquisition and conditioning of the lower limb angular velocity signals. The required low minimum sampling rate suggests that gyroscope data are appropriate for use in bandwidth and battery life limited mobile health applications. Our results also showed that while the commonly employed LPF cutoffs of 5 Hz or less may be appropriate for mid-stance detection, they were not optimal for calculation of heel-strike, toe-off, mid-swing, or angular displacement, obtained with heel-strike and toe-off as delimiters.

AB - The angular velocity of lower limb segments during walking is useful for calculating temporal-spatial parameters and joint kinematics in the inertial measurement unit (IMU)-based gait analysis. While many IMU-based methods for gait analysis have been proposed, configurations of data acquisition and signal conditioning parameter have not been standardized across studies. This study examined the effect of sampling rate and filter design on the characteristic angular velocity waveform obtained from IMUs donned on the lower limbs. Specifically, the frequency analysis of this waveform was performed, and the difference in timing and magnitude of the signal at gait events was evaluated relative to the initial signal. A minimum sampling rate of 35 Hz and a lowpass filter (LPF) cutoff of greater than 10 Hz were found to be appropriate parameters for acquisition and conditioning of the lower limb angular velocity signals. The required low minimum sampling rate suggests that gyroscope data are appropriate for use in bandwidth and battery life limited mobile health applications. Our results also showed that while the commonly employed LPF cutoffs of 5 Hz or less may be appropriate for mid-stance detection, they were not optimal for calculation of heel-strike, toe-off, mid-swing, or angular displacement, obtained with heel-strike and toe-off as delimiters.

KW - angular velocity

KW - digital filter

KW - gyroscope

KW - Inertial measurement unit

KW - mobile health

KW - sampling rate

UR - http://www.scopus.com/inward/record.url?scp=85065414411&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85065414411&partnerID=8YFLogxK

U2 - 10.1109/JSEN.2019.2899724

DO - 10.1109/JSEN.2019.2899724

M3 - Article

AN - SCOPUS:85065414411

VL - 19

SP - 4115

EP - 4122

JO - IEEE Sensors Journal

JF - IEEE Sensors Journal

SN - 1530-437X

IS - 11

M1 - 8642884

ER -