3D Human Motion Capturing Based Only on Acceleration and Angular Rate Measurement for Low Extremities

Schiefer, Christoph; Kraus, Thomas; Ochsmann, Elke; Hermanns, Ingo; Ellegast, Rolf

doi:10.1007/978-3-642-21799-9_22

Cited by 6 publications

(6 citation statements)

References 14 publications

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“…According to the Downs and Black checklist [27], 12 studies were of substantial quality [30][31][32][33][34][35][36][37][38], 10 of moderate quality [39][40][41][42][43][44][45][46][47][48] and one of low quality [49]. Within the studies on kinematics in healthy persons, the methodological quality was 60% on average (range between 42-75%).…”

Section: Methodological Qualitymentioning

confidence: 99%

“…From these 18 papers, 16 focussed on reliability or validity assessment of the applied inertial sensor system [30,31,33,[35][36][37][38][40][41][42][43][44][45][46][47][48] and two studies on the description of kinematics [32,34]. In 12 studies the outcome of the inertial sensor system was compared against the outcomes registered by an optoelectronic or electromagnetic system [30,33,[35][36][37][38][41][42][43][44][45][46]. One study compared the sensors' outcomes to the judgement of trained physicians [47], another to outcomes from videoanalysis [48].…”

Section: Study Design and Population Characteristicsmentioning

confidence: 99%

“…in 6 of the 23 papers ( Table 2). The other systems were reported once or twice and included ADMP Opal [32,49], CoRehab Riablo [46], GaitSmart [34,51], gaitWALK [50], RehaGait [38], Sunnyvale InvenSense [44], Shimmer [39], CUELA [36,47] and H-Gait system [52]. In three papers, the inertial sensors were created from individual components (i.e.…”

Section: Sensor Systemsmentioning

confidence: 99%

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Mobile assessment of the lower limb kinematics in healthy persons and in persons with degenerative knee disorders: A systematic review

et al. 2018

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Inertial sensor systems are increasingly used in the assessment of persons with knee osteoarthritis (KOA) and total knee replacement (TKR). This systematic review aims to (1) investigate the application of inertial sensor systems and kinematics derived from these systems, and (2) assess if current assessment protocols consist of tasks which are, according to the International Classification of Functioning, Disability and Health (ICF) for KOA, relevant for persons with KOA and TKR. A search was conducted in six electronic databases (ACM, CINAHL, EMBASE, IEEE, PubMed, Web of Science) to include papers assessing the knee and one or more adjacent joints by means of inertial sensors in healthy persons or persons with KOA or TKR. Two reviewers checked the methodological quality. Twenty-three papers were included: 18 in healthy persons and five in persons with KOA or TKR. In healthy persons, 11 tasks were related to metrics of the ICF-function and ICF-activity level. In persons with KOA, only walking was assessed. Apart from walking, four additional tasks were related to the ICF-function and ICF-activity level in persons with TKR. In healthy persons, joints located proximally and distally to the knee were assessed, while in persons with KOA and TKR, only the knee and ankle were assessed. This is a shortcoming since hip and trunk motion potentially contain clinically relevant information, in terms of identifying (mal)adaptive compensatory movement strategies. Additionally, physically more demanding tasks should be evaluated as these might be superior in detecting compensatory movement strategies. Former considerations warrant attention in future research.

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Section: Methodological Qualitymentioning

confidence: 99%

Section: Study Design and Population Characteristicsmentioning

confidence: 99%

Section: Sensor Systemsmentioning

confidence: 99%

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Mobile assessment of the lower limb kinematics in healthy persons and in persons with degenerative knee disorders: A systematic review

et al. 2018

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“…The accuracy of the CUELA system and the sensors used in the system has been validated in earlier studies with a multiple-camera motion analysis system (Ellegast 1998; Schiefer et al 2011). In addition, the automatic identification of the five knee-straining postures by the analysis software (Fig.…”

Section: Methodsmentioning

confidence: 99%

Occupational kneeling and squatting: development and validation of an assessment method combining measurements and diaries

Ditchen

Ellegast

Gawliczek

et al. 2014

Int Arch Occup Environ Health

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ObjectivesAs knee-straining postures such as kneeling and squatting are known to be risk factors for knee disorders, there is a need for effective exposure assessment at the workplace. Therefore, the aim of this study was to develop a method to capture knee-straining postures for entire work shifts by combining measurement techniques with the information obtained from diaries, and thus avoiding measuring entire work shifts. This approach was applied to various occupational tasks to obtain an overview of typical exposure values in current specific occupations.MethodsThe analyses were carried out in the field using an ambulatory measuring system (CUELA) to assess posture combined with one-day self-reported occupational diaries describing the durations of various work tasks. In total, 242 work shifts were measured, representing 81 typical tasks from 16 professions. Knee-straining postures were analysed as daily time intervals for five different postures. The accuracy of the method was examined by comparing the results to measurements of entire work shifts.ResultsUnsupported kneeling was the most widely used knee posture in our sample (median 11.4 % per work shift), followed by supported kneeling (3.0 %), sitting on heels (1.1 %), squatting (0.7 %), and crawling (0.0 %). The daily time spent in knee-straining postures varied considerably, both between the individual occupations, within an occupation (e.g. parquet layers: 0.0–88.9 %), and to some extent even within a single task (e.g. preparation work of floor layers (22.0 ± 23.0 %). The applied measuring method for obtaining daily exposure to the knee has been proven valid and efficient randomly compared with whole-shift measurements (p = 0.27).ConclusionsThe daily degree of postural exposure to the knee showed a huge variation within the analysed job categories and seemed to be dependent on the particular tasks performed. The results of this study may help to develop an exposure matrix with respect to occupational knee-straining postures. The tested combination of task-based measurement and diary information may be a promising option for providing a cost-effective assessment tool.

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“…A ZP-flag was set in the logger software to identify the point in time in the data stream. For simplicity the IMUs should point to the ini tial orientation without any motion during a ZP, which allows heading and angular rate to be set to zero, defining the "ZP" [23]. Using Eq.…”

Section: Zero Pointsmentioning

confidence: 99%

Optimization of Inertial Sensor-Based Motion Capturing for Magnetically Distorted Field Applications

Schiefer

Ellegast

Hermanns

et al. 2014

Journal of Biomechanical Engineering

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Inertial measurement units (IMU) are gaining increasing importance for human motion tracking in a large variety of applications. IMUs consist of gyroscopes, accelerometers, and magnetometers which provide angular rate, acceleration, and magnetic field information, respectively. In scenarios with a permanently distorted magnetic field, orientation estimation algorithms revert to using only angular rate and acceleration information. The result is an increasing drift error of the heading information. This article describes a method to compensate the orientation drift of IMUs using angular rate and acceleration readings in a quaternion-based algorithm. Zero points (ZP) were introduced, which provide additional heading and gyroscope bias information and were combined with bidirectional orientation computation. The necessary frequency of ZPs to achieve an acceptable error level is derived in this article. In a laboratory environment the method and the effect of varying interval length between ZPs was evaluated. Eight subjects were equipped with seven IMUs at trunk, head and upper extremities. They performed a predefined course of box handling for 40 min at different motion speeds and ranges of motion. The orientation estimation was compared to an optical motion tracking system. The resulting mean root mean squared error (RMSE) of all measurements ranged from 1.7 deg to 7.6 deg (roll and pitch) and from 3.5 deg to 15.0 deg (heading) depending on the measured segment, at a mean interval-length of 1.1 min between two ZPs without magnetometer usage. The 95% limits of agreement (LOA) ranged in best case from -2.9 deg to 3.6 deg at the hip roll angle and in worst case from -19.3 deg to 18.9 deg at the forearm heading angle. This study demonstrates that combining ZPs and bidirectional computation can reduce orientation error of IMUs in environments with magnetic field distortion.

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3D Human Motion Capturing Based Only on Acceleration and Angular Rate Measurement for Low Extremities

Cited by 6 publications

References 14 publications

Mobile assessment of the lower limb kinematics in healthy persons and in persons with degenerative knee disorders: A systematic review

Mobile assessment of the lower limb kinematics in healthy persons and in persons with degenerative knee disorders: A systematic review

Occupational kneeling and squatting: development and validation of an assessment method combining measurements and diaries

Optimization of Inertial Sensor-Based Motion Capturing for Magnetically Distorted Field Applications

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